We Buy Anything

"The sign said, "We Buy Anything!" so I went inside, gobbed on the counter and barked "How much for that then?""

- Bill Bryson

"Tip two, pick up everything - everything - and sell it. Everything. Crisp Basilisk Urethra? Pick it up. Put it in your bag. There's somebody out there who wants that."

- Penny Arcade

In video games, regardless of a vendor NPC's specialization and location, they will never refuse to buy items from you. And they will never run out of money.

That's right, a bread baker in a poor village will gladly pay you for anything from Vendor Trash to the Infinity+1 Sword, as will a renowned shield crafter in a capital city. What exactly do they do with these items depends on the game. If you're lucky, the same vendor will offer them for sale at triple the price (even if it has nothing to do with the items they usually sell); otherwise, they will vanish without a trace and be gone forever.

It is unknown how these vendors make a living; they can't profitably resell the things you sell to them, since all the other vendors in the game usually pay the exact same prices for the same items. This especially applies to the vendors in World of Warcraft that are unlucky enough to be the closest to the Auction House, bank or mailbox: nobody ever buys anything from them, but everyone uses them to dispose of their junk.

Of course, this is done for the player's own good, so they won't have to run in circles seeking a vendor that would buy a particular item: they can just sell all of their Vendor Trash in one go.

This is unrelated to the situation where, in an effort to keep the player from disposing of an unknown but important quest item, all stores either refuse the sale or pay $0 for it.

Compare with We Sell Everything.

Action Adventure

 * The Legend of Zelda Majoras Mask also had the "curiosity shop", where you could sell fairies, bugs, Zora Eggs, and fish. All they ever sold was a stolen bomb bag, a stay-awake Mask of Power, and your own sword (or jar) when it was stolen by a bird. Very Shady.
 * The Legend of Zelda Ocarina of Time had a hyperactive townsman who bought anything, including icky bugs.

Adventure Game

 * Maniac Mansion has a company that publishes anything.
 * Those exist; it's called Vanity Publishing.

MMORPGs

 * One must feel sorry for the vendors closest to the auction houses in World of Warcraft. Nobody ever buys anything from them, they're just used as dumps for whatever vendor trash an adventurer happens to have, and a repair station for gear the characters wear or are about to sell.
 * Many players (And at least one webcomic) have joked that the money vendors get from repairing gear would allow them to buy a country.
 * You can sell anything to any vendor, even selling epic weapons to the fruit merchant in the forest, or the poor Forsaken selling cockroach pets under the steps in Undercity.
 * A particular example comes from Runescape. All items can be sold at a general store. However, certain shops that deal in a more specific area of business might only accept certain items; like how a shield store would only buy shields. But selling items to these specialty shops can earn more money than selling to a general store.

Real Time Strategy

 * Spellforce is particularly egregious. You pick up an absurd amount of loot in this game, the majority of it totally worthless to you until you take it to a merchant. Irrespective of what he sells, he'll give you a price for it. After a couple of levels, currency becomes literally completely worthless as you have more money than God. It's less frustrating than having to find the relevant merchant (considering not everywhere has them, and Greyfall has like fifteen merchants, all selling slightly different flavours of the same worthless trash (which is worthless almost before you leave the town).

Role Playing Game

 * In Pokémon, the Poké Marts will buy any item that isn't a key item, although at half price of the original value.
 * Oddly, they can buy the Moon Stone and Master Ball (which isn't sold in stores), but for free. Then again, if you're stupid enough to sell the one-of-a-kind Master Ball, you probably deserved getting nothing for it.
 * While the SNES Lufia games obey this trope as far as all vendors buying what you sell without exception, they do provide an explanation to what happens to sold items: they are shipped to Forfeit Island, an island that sells exclusively merchandise you have sold in shops elsewhere in the world.
 * While Valkyrie Profile: Silmeria allows you to sell any item to any shop you find, in order to gain access to the best buyable gear, specific items have to be sold to specific merchants.
 * Fallout merchants have a finite (but renewable) supply of coins, but will still buy literally anything, including plot items and stock stolen from their own shop. In Fallout 1 and 2 it will remain in stock for you to buy back later (usually, anyway) and certain vendors will offer better prices for certain items. Lampshaded in Fallout 3, as Moire Brown cheerfully reminds you "Remember, I'll buy whatever you're selling". Of course, this is doubly fitting as she ropes you into doing field research for her book, and it's pretty easy to feed her false information.
 * One vendor in Fallout 2 even allows you to steal cash, which allows you to buy their entire stock and steal all your money back in one go.
 * It's also partially justified in that there may actually be a market for random bits of junk in the Fallout universe: since there aren't exactly a lot of resources available, it's not implausible that someone might find a use for old tin cans or whatever. This is especially evident in Fallout 3, where you can craft weapons out of scavenged junk. Indeed, many Fallout 3 merchants sell junk items, and one caravan specializes in it.
 * Even more strangely than this, every single friendly character will barter anything at all from you in the first two games, regardless of where they are or what they might be needing, although they usually don't have much to offer. Sometimes (if they don't have it equipped) they're willing to sell their only weapon in the middle of wilderness!
 * In Earthbound, you could acquire a FOR SALE sign. Using it in any location, be it a city or a secret, alien controlled cavern, will cause someone to come by, and ask what you're selling. They will buy anything from you at the same price a normal store would. Although if one is inside a dungeon, you will eventually get a call from a potential customer complaining that they couldn't get to you. How they got your unlisted cell phone number in the first place is another matter entirely.
 * The game even jokes about the ridiculousness of the situation. The patrons to your "shop" will say things like "Thanks! This is exactly what I wanted!" and "This was definitely worth the trip out here!"
 * Final Fantasy XII plays this straight to bizarre extremes. Your primary means of raising money is collecting and selling Vendor Trash. Any shopkeeper, including wandering merchants, will buy any of this (as well as any old equipment or extra items you wish to sell.) Keep in mind that the loot items you can sell range from innocuous stuff like wolf pelts and cactus fruit to things like meat that is so tainted that eating it condemns you to eternal damnation, or grimoires that give details on spells that could destroy the world.
 * Shopkeepers also have unlimited gil to buy your stuff with, which leads to some really strange sequences - you can sell thousands and thousands of gil worth of loot to a guy who ostensibly doesn't have enough gil to pay for a river crossing. (You're exempt from this fee because in order to get the crossing to run you first help the villagers with a problem they're having, but it makes you wonder how much they normally charge...)
 * The aforementioned loot items, no matter how mundane, can be used to create all kinds of items. While they're often just potion six-packs, or something like that, they occasionally turn out to be something like the Infinity+1 Sword, which raises the question of how a shopkeeper managed to craft Ye Olde Hammer Of Massive Internal Hemmorhaging out of pebbles and wolf musk.
 * Kill enough of specific enemy types and the game actually gives you answers to that.
 * My World, My Way does this, although you can pick up the items again from the same different merchants in other towns after you've sold them.
 * Aside from selling every kind of weapon or armor the characters need, Officer Kurosawa from Persona 3 can buy anything they come across --particularly, the inexplicable equipment that appears in the inexplicable treasure chests that generate within the inexplicable, otherdimensional Evil Tower of Ominousness that appears out of thin air in place of the local high school.
 * The same happens with the owner of Daidara Metalworks in Persona 4 who takes Kurosawa's place as the game's primary equipment vendor, and will also purchase anything - and indeed needs to be sold all the Vendor Trash you scavenge off of Shadows, because these new materials expand his inventory.
 * In Persona 2, any shop will buy whatever you have on hand, though they only sell specific things; stuff you sell off is consigned to oblivion.
 * Justified in Shin Megami Tensei: Strange Journey. Instead of a store, your home base is outfitted with a manufacturing lab, which uses raw materials ("Forma") and energy units ("Macca," the currency of the demon world) to produce equipment and consumables. So, if you have unneeded items in your inventory, you can take them back to the lab to be disposed of. While the materials are lost, you can salvage some Macca in return --in effect, "selling" the items at a loss.
 * In Recettear, you ARE the person who buys everything. You also Sell it back to the community for profit.
 * In Exit Fate, all shopkeepers will buy anything you sell them except any spells, even if they themselves sell spells. Possibly justified by how spells work and interact with their users.
 * Lampshaded in Shining Force. If you sell something to a shopkeeper that he doesn't sell in his store, he'll say "Thanks. I don't sell this, but I know someone who does!"

Simulation Game

 * Aerobiz: The "World Lease" corporation will purchase any aircraft and at any quantity from you. Got a '40s era, piston-powered Douglas DC-4 to sell in 1975? We'll buy it for half the price you purchased it! Got 20 brand new B747-400's? We'll buy them for half the price you purchased it, no problem!

Wide Open Sandbox

 * In Chu Lip, it's possible to sell the Poopie you fish out of garbage cans to the various stores scattered about Long Life Town.
 * All the traders in Terraria will buy anything you offer them. You can buy the items back for the same price until you close the interaction window, at which point they'll be gone. They even accept items that are considered worthless, but they won't pay for them. You'll have to, though, if you want them back, as they have suddenly gained value.
 * In The Sims Medieval, you can sell most of the things you gather, even byproducts that seem worthless. You can sell pond scum.

Live Action TV

 * One of the newest types of reality tv shows centres around people who will buy and sell all sorts of weird odds and ends, which often seem worthless but can be resold for a high price to the few people who are willing to pay for them. Pawn Stars centres around a family-owned pawn shop whose staff will buy just about anything they think they can resell in their shop, while shows like American Pickers and Auction Hunters centre around people who visit rural communities or bid on the contents of unclaimed storage bins and buy a wide variety of things that they then resell to interested buyers.

Web Comics

 * Parodied in this GC strip upon trying to sell off an item in a weapon shop.

Hack and Slash

 * Likewise, in Diablo II, there is an upper limit on the amount of money a particular vendor will pay, depending on the player's location. In the First Town, items cannot be sold for more than 5000 gold, but this limit scales upwards in subsequent towns. In addition, since trade screens are limited in size in this game, vendors will accumulate items sold to them by the player as long as there is enough space for them on the screen, and subsequent items will disappear.
 * They'll still buy ANYTHING mind you, and they still have infinite cash reserves. The limit only applies per item.

MMORPGs

 * In City of Heroes, stores will buy Enhancements, but not Inspirations. You're less likely to want to get rid of excess Inspirations, however. As well, while any store will buy any Enhancement, you'll get the best price if you sell at a store that sells the same type of Enhancement. Contacts won't buy either, but will buy recipes and salvage.
 * However, they will buy recipes and salvage at a set price, which is often FAR below the going market price if you sell them to other players.
 * Some recipes and salvage are in such low demand that they are effectively vendor trash much of the time. Especially most recipes found before level 20.
 * Also, a few areas have a single store that pays the same price for anything you bring them. This is mostly for practicality as it makes little sense to have five vendors hanging out in the Vanguard base to do the job of one.
 * Kingdom of Loathing parodies this trope with the "autosell" function, which allows you to sell items from your inventory to a bizarre randomly-generated passer-by. This has the same result of arbitrary amounts of worthless items magically becoming money, with "hotel detectives", Dutch Elm Disease-riddled Ents, intelligent shades of blue, and other surreal entities taking the place of the all-purchasing vendors.
 * In the MMORPG Tibia, a few shopkeeper NPCs actually buy from the player, and even then, you'll usually have to talk to a different NPC about selling weapons than selling armor. Prices also vary from town to town.
 * In order to avoid the Money Spider trope, many monsters in WOW tend to drop useless items instead of money, some of which are pretty bizarre goods. But hey, the NPC vendors buy anything (even the mechanical repair bot that can be crafted by experienced engineers, which is mostly there for, as the name implies, repairing your equipment in the middle of nowhere (usually raid dungeons).
 * Anything you sell to a merchant can be bought immediately back for the exact same amount of money they bought it for.
 * Ditto in Runes Of Magic.
 * Achaea has almost no Vendor Trash, and the only opportunities to sell items come during quests or when trading with other players. Quest NPCs are only interested in the particular item they asked you for in the first place, but do seem to have infinite gold.
 * In the MMORPG Fly FF, while shops will buy most of the stuff you pick up, there's quite a bit of Vendor Trash - certificates, maps and letters for example - that they won't touch. Wandering sellers don't buy anything from you. Shows they're not complete idiots.
 * Although merchants in Guild Wars will buy pretty much anything, most of them pay only a trifle unless you bring them something of the type they specialize in, in which case they pay market value, based on the supply and demand of other players buying and selling the same item. (The items still cost more if you're buying than if you're selling, though.)

Real Time Strategy

 * While not an RPG Victoria an Empire Under The Sun averts this: If you want to sell something, someone has to be willing to buy it. Usually this is not a problem, but it is possible to start producing say, cars or airplanes before POP's start demanding them.

Roguelike

 * As in so many other of its aspects, Nethack doesn't care about the player having an easy time. Most shops specialize, and will neither buy nor stock items that don't match their theme. Of course, that doesn't preclude the existence of the occasional General Store... Also, shopkeepers can run out of money, but will offer you credit if they do.
 * Keep in mind that, even though shopkeepers won't buy what they don't specialize in, if you accidentally leave anything on their premises (such as all your possessions and your corpse...) they will gladly take those possessions and start selling them. Even if such items are so worthless even general shops won't buy them.
 * Yes, you can, in fact, purchase your own corpse.
 * Roguelike Ancient Domains of Mystery also has specialized shops that tend to only buy the type of item they sell. For example, the shopkeeper in the first town will only buy food (even if it's inedible rotten meat), not weapons or other supplies you may have picked up along the way.
 * In Castle of the Winds you can only sell goods you find in the dungeons at the same shops where you might buy those things (i.e. you can only sell swords to a weapon shop, or a suit of plate mail to an armor shop). Additionally, they won't buy items you know are cursed, or unidentified items if you've sold them too many cursed items (you can get around this by Save Scumming). There are, however, junk shops that will buy anything for 25 copper pieces or its market value, whichever is lower. A few items fetch more money broken than working, but you can't break them yourself.

Role Playing Game

 * The slightly obscure (and fantastic) steampunk fantasy RPG Arcanum: Of Steamworks and Magick Obscura has nearly all of the shops specialize, only buying or selling certain items (with the exception of the junk dealers, who exist in-game for the sole purpose of buying everything). Tailors will only buy or sell clothing, a gunsmith will only buy guns, a blacksmith will only buy weapons, armor, and the stuff required to make them, etc.
 * Unless you have training in haggle, then it is a proper example.
 * The Elder Scrolls 3: Morrowind completely avoids this trope. Characters have limited and finite amounts of gold on them, after which they will not be able to purchase anything until the player purchases items from them or time passes. Likewise, they will largely refuse to purchase items that are too different from their normal wares -- a fine clothing store won't buy armor, a jewelry shop has no use for weapons or magic scrolls, and most merchants won't touch any of your goods if you're carrying the potent drugs skooma or moon sugar. There are two exclusions, however, in a talking mudcrab and a talking scamp, both of whom will purchase nearly everything and have vast supplies of currency.
 * Their supplies of currency are not particularly vast, which becomes evident once one tries to sell them artefacts. These things tend to cost a few times over their monthly allowance. It is still possible to sell them artefacts with the help of bartering, but that might be considered a puzzle of itself.
 * And also, though the mudcrab has more money, it is also out in the middle of nowhere which makes it much less practical. Meaning that most players use the scamp, which has half the mudcrab's amount of money, which means selling anything you get at higher levels takes several in-game days and a very good knowledge of math. This begins to get absurd once you start trying to sell stuff worth over 100,000 gold to a scamp which only has 5000 gold and all the junk you sold to it before.
 * This is precisely why the easiest way to play the game is with a thief-ish character who has Alchemy as a major skill. Thief so you can have a near-inexpendable supply of ingredients, Alchemy so you can turn those ingredients into semi-valuable and rather light-weight potions. When you start off, you'll generate a glut of potions for restoring fatigue, poison, etc... and then you'll pretty much only use them for trading.
 * Another notable aspect of the aversion is that things sold to merchants are not lost forever, but rather enter the merchant's inventory unless the merchant decides to equip the item and wear it (thus forcing you to kill said merchant if you ever want it back). This is particularly jarring when you sell, say, a set of Dark Brotherhood armor to a merchant, who promptly dons it and then resumes business as normal while dressed as a stealth assassin. It's also rather amusing to see poor pawnbrokers pimped out in full glass/daedric gear.
 * Merchants also kept the money you payed them with. This could come in handy when you went have a mage make a particularly expensive magical item for you. After paying, you could sell the mage who now had 300.000 coins a stack of the Daedric Infinity Plus One Swords that had been clogging up your inventory, and get all your cash back.
 * The Elder Scrolls 4: Oblivion has this to a degree. Initially vendors will only buy and sell whatever category of items they specialise in. If the player has sufficient "Mercantile" skill, they will begin accepting other kinds of items. Additionally, there is a curious limit on the amount of cash they will pay for a single item. The highest limit in the standard game is 1200 gold, so if one tries to sell an item estimated to be worth 2000 gold, one will only get 1200 in the best case. Yet if one has two such items and sell them separately, one will get 1200 each time. Effectively, merchants have unlimited cash, but only part with it in rather limited chunks. A fact of much debate among some players is that several of the downloadable content packs for the game introduce vendors who have a cap of 2000 gold.
 * There are a number of stores, such as Jensine's in Imperial City, that will buy anything except illegal goods. Some vendors will buy even those, but you need to be a thief to find them.
 * The sequel Skyrim keeps to this theme - if you are not skilled in Speech, you'll have to content yourself with the usual ways, but as soon as you get halfway to the max skill level you can unlock a perk that makes it possible to sell anything to anyone. At 70, you can invest money into specific shopkeepers to make them have more gold for you, at 90 you can sell stolen goods to any vendor and at 100, the max level, every merchant in the world gains a large increase to their permanent available gold. Yes, everyone. Amusingly enough, this means that you can now walk into any shop, even taverns, travelling merchants or random street peddlers (who normally have a very low amount of gold and mostly sell food and drink) and sell them stolen, high-level magical armor for the highest price possible. Why exactly your average street vendor suddenly decided to accept these kinds of items is never explained. Perhaps, as the skill implies, you're just very persuasive.
 * Paper Mario: The Thousand-Year Door has a very slight aversion: although any shop will buy any item, they do not all value them the same; there were at least two money-making schemes in-game that relied on this.
 * SaGa Frontier and its sequel subvert this trope by making only specific vendors for the express purpose of selling items (and only certain ones, at that). Other vendors will only sell goods.
 * Jade Empire averts this trope entirely, as Essence Gems are the only non-quest items in the game, and so everyone is willing to buy and sell them.
 * Fable subverts this by having traders only buy items they're interested in, but as an apology the traders are often especially interested in other items and will offer a higher sell price.
 * Also, in Fable 3, you can sell your items at a pawn broker, who will usually take anything you have, but has a limited amount of money to give you.
 * In the Might and Magic series of games shops will usually only deal in their specialty, weapons shops will only buy weapons, armor shops armor and magic shops magic item. There are general stores, but they buy at much lower prices than the other shops.
 * The Wizardry series has only specialist stores (though "specialist" varies pretty widely), who only buy the sort of items they sell. However, since they'll pay for anything as cheap as a small bundle of arrows (2 gold) to expensive as a phaser (about 45000 gold), even though they personally only carry a small amount of money (that you can steal), it fits the trope otherwise.
 * The Neverwinter Nights toolkit allows module builders to place restrictions on the types of items that their merchants will buy, and they can also be given a finite gold supply. And in Neverwinter Nights 2, merchants have a finite gold supply even in the official campaign, although they still buy anything.
 * NWN1's main campaign played this straight... except for Booby Trap construction kits, which were always flagged as "stolen". You know, as opposed to everything else your Kleptomaniac Hero is pawning off.
 * In Hordes of the Underdark and Neverwinter Nights 2, vendors would have an infinite total gold supply, but would have an upward limit on the gold they would offer you for a single item. A merchant not willing to pay more than 10,000 GP for 99 arrows will have no problem paying 10,000 GP for 33 arrows three times.
 * In Legend of Dragoon you have two or three different types of shops, typically divided between Items and Weapons.
 * Most shops in Breath of Fire III fit this trope, except the Junk Shop in the Faerie Village. Certain items will sell for much more there.
 * Ultima I had a cute response if you tried to sell food back to the food vendor: "Used food? No thanks!"
 * Mild aversion in Divine Divinity. The merchants will buy anything, but they have limited gold, and certain shops will only sell certain equipments (late game not counting).
 * In the original Gothic, traders would buy anything, but some items were 'junk' and worth zero (although the trader would still take it from you if you offered it). Traders could run out of money, and by the end of the game, usually did. In the sequel, the trading controls were fixed to be more intuitive, one of the side effects being that traders now have infinite gold.
 * On a different note, vendors buy items at reduced price, but specific ones accept certain items at full price, for example, the master hunter of Khorinis buys pelts; although most of those are quest-related.
 * In The World Ends With You, you can't sell your goods to a vendor. You have to sell it to, um...the trash can icon on your pin menu, which will accept anything.
 * Except for your non-pin items and the pins that are "more valuable then all the money in the world", which includes the Red Skull pin that drags down your speed.
 * And
 * Averted in Baldur's Gate. Shops won't buy non-magical projectiles, (they probably get arrows the same way everybody else does - off bandits' corpses), Cursed Scrolls, or pathetic weapons like Quarterstaffs or Slings. Not all shops buy weapons or books either. And if you sell them an unidentified magic weapon, they'll buy at the price of a regular weapon, identifying it at the same time, while you stare and say, "I just sold a +2 Long Sword for 37gp?!" Also, different shops offer different prices on items and after ten game days they'll sell what you sold them, unless it's an item vital for game completion, in which case you'll just have to buy it back.
 * Both Icewind Dale games also had an amusing "supply and demand" mechanic : if you kept selling the same kind of item to a vendor over and over, the buying price would go down. Meaning eventually, merchants could offer you less gold for the ubiquitous +1 Longsword then for a regular Longsword. Equally amusing, the prices would only go down after a completed trade, so hogging hundreds of +1 Longswords in a Bag of Holding and selling them in bulk was much, much more profitable than selling them one by one. Oh, and of course, even if you drove one merchant's prices down to ridiculous levels, the merchant 5 feet away would still be more than happy to offer you the full price.
 * In Crystalis, you can only sell your items in specially-marked pawn shops that will take any unwanted armor or items off your hands.
 * Quasi-inverted in Great Greed for the Game Boy, a JRPG with an environmental slant, where shops recycle (it's still Lost Forever) your equipment and any of the useless flavor items (like that fancy dress). This is also the only way for you to get rid of any TRASH you picked up in a random chest, and thus free up your very limited inventory for something useful. All you have to do is pay a sizable fee. (Since you don't have a portable garbage dimension, you cannot leave Trash alongside a road -- unlike your heal potion or dentures. It also comes off as the stores are penalizing you for recycling.)
 * Slight aversion in Tales of Phantasia. There are a set of items known as trading items which you find scattered around the world; each town will pay a different price for them, and the trick is to know which items to sell where.
 * In Geneforge 1 and 2, each vendor only has a certain amount of gold. This will go up when you buy things from them, and go down whenever you sell something to them. It is possible for every vendor in the game to run out of money, making it impossible for you to sell anything (of course, that means you have all the money, so you don't really need to sell anything). The gold limitation disappears in later games.
 * In Golden Sun, all merchants will buy everything. If the thing you're selling is in some way unique, you can buy it back, but only from a shop that sells the corresponding type of item. Any shop of that type. How exactly your Infinity+1 Sword instantly teleports from the hands of the cute item shop girl to every weapons salesman in the world isn't exactly clear.
 * In Mount & Blade, every merchant has a set amount of money, so you can't sell too much (unless you buy some stuff at the same time). Moreover, some items will sell for different prices in different cities, and if you sell several of one thing you'll lower its price. (Works the other way too.) However, if you leave a city and spend a little time away, when you come back the merchant will have a refreshed inventory (the stuff you sold will be gone) and he'll have some money again. Because everyone buys everything, if you happen to clean out the goods merchant for example of all his silver denars but still have a few items to sell, then you can turn around and sell the rest of your items to the horse merchant, the arms merchant, or the armor merchant, regardless of whether you're selling oil, linen, or armor acquired in battle.
 * Averted in the first Aretha RPG for the original Game Boy. Equipment can only be sold at pawn shops and each pawn shop will only accept three particular items, and they only start showing up a considerable distance into the game. It is not the best system of its kind ever implemented.
 * Partially averted in Lands of Lore: The Throne of Chaos. Blacksmiths and fletchers will buy any unwanted equipment you care to sell them, but fletchers will pay more for bows and other ranged weapons than blacksmiths will, and blacksmiths will pay more for melee weapons and armor.
 * Averted heavily in the classic CRPG Wasteland, in which stores will only buy items that they sell. Stores even keep track of inventory, including the items you sell to them. This can be a great way of storing items in excess of your carrying capacity - selling items to stores and then buying them back later when they are needed.
 * In Dragon Quest VIII, certain items (typically, those you can't buy in stores) will devalue if you sell too many, but you can keep selling them anyway if you like. Interestingly, the upgraded herbs sell for drastically more than the starting price if you sell enough of them, which makes for an interesting (if extremely time consuming, given the mechanics of the alchemy pot) money-making scheme.

Simulation Game

 * In Animal Crossing: Wild World, Mabel will buy shirts, hats, masks, and umbrellas, because that's what she sells. On the other hand, Tom Nook, who runs the general store next door, will buy shirts, hats, masks, and umbrellas, and nearly everything else. He'll even accept valueless items which would normally have to be disposed of in the Town Hall's recycling dumpster: In fact, if you attempt to sell him nothing but worthless items, he'll rather ecstatically comment that the disposal of such items is yet another of his many services. (The more attentive player has to think, "Why is he still willingly buying millions of dollars worth of peaches?")
 * Money laundering, of course. Everyone knows that Tom Nook is the Nookfather.
 * In the Railroad Tycoon games, stations will only buy commodities if a local industry needs them. Only a station with a bakery will buy grain, and so on. Also, stations must reach a minimum population size before they will buy passengers, mail, and other goods. (At normal difficulty levels. Easier levels enabled We Buy Anything mode.)
 * In Sid Meier's Pirates!, each town you visit has a limited amount of gold that it can pay for items with (and limited supplies to sell). However, leaving the town and immediately turning your ship around lets them restock their cash reserves and supplies.
 * While keeping in mind that a week of game time passes whenever the player stops at a town.
 * In Harvest Moon: More Friends Of Mineral Town, you can unlock a feature where you can sell items to Won instead of shipping them. Won usually pays more for said items, and also buys some items which you cannot ship. Even though Won apparently doesn't even have enough money for a proper stall or his own house.
 * Why would he buy a house when he can take advantage of Zack's hospitality?

Turn-Based Strategy

 * The Shining Force game series doesn't change the formula much, except that if you sell a vendor something that doesn't fit their product line, they mention off-hand that they know someone who they can sell it to. Either way, most vendors have a "discount" section in their store, which is basically just the stuff you sold earlier in the game (which somehow teleports from town to town...)

Wide Open Sandbox

 * In Space Rangers 2, you can sell any type of goods (like food, medicaments, drugs, etc.) and equipment (including unusable Dominator equipment) on any planet. However, some goods are marked as "illegal" on some planets (drugs are banned almost everywhere) meaning you cannot sell those without ruining relations with that planet, and Dominator parts sell as junk, unless given to science stations, which specifically ask for those.
 * In S.T.A.L.K.E.R.: Shadow Of Chernobyl different NPCs will not buy certain types of items, and most whom you meet in the general world have a finite supply of funds. Only the major questgivers have unlimited funds.
 * S.T.A.L.K.E.R: Call of Pripyat, and possibly Clear Sky, take this even further, where NPCs will refuse to buy weapons and armour that are below a certain threshold on their condition level.

Non-Video Game Examples

 * Cracked Photoplasty advertises such a shop in Ads for Products That Must Exist in Video Games.