Just like I don't see the +2 sword or whatever you write or erase from your character sheet in DnD as a "mechanic", I thought it was pretty clear barter was just money.
It's money that might come in the form of a necklace or shoes or even bottlecaps, but it's just money. So roll+barter's a mechanic, as a move, but barter's not a mechanic, it's just stuff.
It's up to the GM and the player to decide how much it's worth in each situation.
The FED is dead. But it's probably just different ways of looking at the character's stuff.
Here's a semi-related question: for the manipulate move, the book says you need leverage, right? Is it up to the MC or player or the NPC or what as to what leverage is, in this situation?
Or is there a "soft rule" here that's about temptation? Because say I offer Johnny the NPC a valuable knife to murder his sister and get a 10. He's got to do it; there's leverage I guess, and the player made the roll. But Johnny likes his sister more than the knife; he doesn't even really need the knife. Does he HAVE to do it, because of the roll?
Or does he get to say "that's not important to me; that's not leverage TO ME"? Because if so, that's makes the manipulate and seduce move less effective, almost irrelavent. If I can only manipulate when I have something that they really want, do we need a move there? If that's the case, it's just sort of working itself out at the fiction level. Or is it just a mechanical way to back up the leverage?
EDIT: Or maybe the roll is making him want the knife, representing the rolling character's smooth move? Hmmmm.