TRADE & BARTER
"Commonly available" items include things on the Inventory insert or that could be found in any household (like a bucket or quern stone). See Common items for a list of examples. Folks trade, loan, and gift these items all the time; no roll is required to acquire them (and there's no real point in "selling" them). If you like, ask the PC how they acquired it, from whom, in exchange for what, etc.
Unique and truly exceptional items—like arcana or "the key to Mutra's vault" are beyond the scope of this move. Should the PCs want to acquire such an item, or sell it for anything close to its real worth, they must Make a Plan or wait for a trade opportunity.
"Special items" are things in short supply. They're not necessarily valuable, but they're not freely available. See Special items for a list of example special items.
PCs don't have to roll to acquire special items that they already own or have access to—a PC with the "smithy" special possession can just have a reasonable number of nails, metal tools, etc. But if a PC wants to acquire a special item that they don't already possess, or sell any special item, that requires a roll.
Players subtract a special item's Value (see Value and coins) from the roll, which makes high-Value items difficult to acquire or sell via this move. Even Value 0 special items will often be unavailable. That's intentional.
On a 10+, say who's able and willing to trade, and establish what the NPC is offering or willing to accept. Local NPCs might be willing to loan or just give the PC low-Value items. Otherwise, it should be a fair trade, within the same Value tier (see Value and coins).
On a 7-9 when the PC is looking to sell,
present an NPC who's only willing to give something of lower Value. Like, if the PC is selling a Value 2 item, they might offer a few Value 1 items—or even just one such item! Maybe they don't really want what the PC is selling, or maybe they're angling for a good deal.
On a 7-9 when the PC is looking to buy...
- ... picking "it'll cost more than usual" means that the NPC wants something of a higher Value, or a really good exchange rate, or an added favor, debt, or service. Establish what they're asking, and make it clear that the NPC is willing to walk away from the deal.
- ... picking "___ has it, but isn't keen to give it up" means that someone currently in town has what the PC is after, but they don't want to trade (or at least, they don't want to let the PC have it). Say who it is and establish the nature of their objection.
- ... picking "something close, but not quite right" means that what the PC wants is unavailable, but there's a substandard alternative. Like if they want a good tracking hound, maybe they can get a half-feral cur. Or if they want a purse of silver coins, maybe they can get only a handful.
Feel free to offer the player a choice on a 7-9. "Well, you could borrow Gunter's blind old hound. Or you could ask Owain for one of his good boys. Except, he hates your guts. What do you do?"
Once you've established who's willing to trade and their initial position, ask the PC what they do. If they try to haggle, play out the scene. They might be able to Persuade or otherwise convince the NPC to accept better terms. Or they might reject the deal. Or they might try to steal what they're after. Play to find out what happens, no?
On a 6- to Trade & Barter, you do not get to make a hard GM move (and the PC doesn't mark XP). Instead, you just tell them no one in the village has the item to trade or is interested in what they're selling. Tell them where they could go and try again. If they don't want to make a trip, they can try again next season.
When the PCs visit another community, the Trade & Barter move still applies but what's commonly available changes. In Gordin's Delve, for example, bronze and steel weapons are common, as are weapons of war. But among the Hillfolk, even irontipped spears and arrows are special items, requiring a Trade & Barter roll to acquire or sell them.
When the PCs roll to Trade & Barter in another steading, they roll with that community's Prosperity. If the steading is a hamlet, they roll with disadvantage. If the steading is a town or a city, they roll with advantage.