I love this format! I’ve got some questions: How do we determine market value? How do we bridge the gap between card value and, say gold piece value in a RPG? What if there’s only 2 players and they don’t want to concede a +2?
Great questions!
The market value is determined by the 6 cards you draw - the average value of those cards is the market value. If you're applying this to an in-game item then it will depend on the item and system you're playing. If you want to translate that to a gold piece value then it might make sense to multiply it by 10 or 100 and then play the game as normal from there.
Alternatively, you could set the value independently of the cards and then use the negotiation result as a modifier for the value. For example, if the outcome of the negotiation is that the remaining two cards total half of the market value determined at the beginning then you can halve the value of the item being sold.
If no one wants to concede the +2 then they need to be more reasonable and admit when someone made a good argument - that's very much up to how you play and how reasonable people can be, which is why having an arbiter is quite useful. If you're playing this in another game then the GM can act as the arbiter.
I'm glad you're enjoying Hard Sell! I'm happy to answer any more questions here :)