I think it was Secret of Evermore for the SNES that first opened my eyes as to haggling as an option for buying items. I know some other games like Chrono Trigger had the 65 million B.C. needing to get petals and claws instead of your shiny rocks to get things, but it wasn’t until the market scenes in Evermore where I found myself thinking not in ‘how much GP is everything going to be’ but instead ‘okay, I need this many chickens and this much rice to get the Artifacts for the dealer to give me the items I need to exchange for the treasure I want’. If I knew of the market coming ahead of time, I might have grinded for more GP to be able to get everything, but at the time it was a surprise.
It is akin to a trading quest, but all the NPCs are in close proximity and I don’t have to remember that someone from so many screens away wanted some object. I was also initially on a timer so you had to act fast to get what you wanted. Fifteen minutes to find the trades and get items to make them.
This is what I find strange in a lot of roleplaying games when they put a price value on things. It becomes a metagaming experience for players, as they can quote that item X has a written price of Y so they should be able to get that for it. However, in roleplaying terms, three things are wrong with that image.
First, characters do not have a price list of the items.
Second, there is likely work that may need to be done to get the item sale-ready.
Third, the merchant does need to turn a profit on the sale of items so they need to undercut (also, they now have an item that has to sell to be of any use to them).
TV is full of Storage Wars, Pawn Stars and other such wheeling and dealing people getting items at the best prices they can and trying to sell it for a profit. Sometimes, it can be used to trade for something else that they want, as is seen in the Deep Space Nine episode Progress , as Jay and Nog do what boils down to a trade quest to get their prize. It can work though if its player driven rather than GM arranged, as if they are seeking buyers they take an active role.
I used to do this a lot in Shadowrun games, have the players loot items from the guards or even things like files or research or other specs the target had on hand and then sell it to a fence. It can also work in other games, stealing items and things and selling them; the system Shadowrun used was a negotiation roll starting at 50% value and then you mark 5 percent up or down depending on who won and by how many successes. In d20 type games could have it based off how many points they beat them by or set a difficulty based on their diplomacy or appriase skill and decide that way. Just remember, everyone must make profit from selling the item so they have an upper limit on what they will spend so they don’t take a loss.
By allowing bartering, you also introduce the possibility of value placed on things beyond items in the ‘Equipment’ chapters. In a fantasy game, this could be the beginning of a king maker plotline as players establish favor by promising favours to a specific person or group. It could also be the cop turning a blind eye to actions of a criminal organization for a reduction in how much money the PC owes them. It could be the technician fixing an heirloom in exchange for the player (or party) doing some specific quest, which is usually the way a lot of plot hooks are, but sometimes maybe it is even something simplier like in Shadowrun I had players do a mission for a farmer who would then send them some farm fresh food every so often. It was like those monthly packages showing up on your doorstep, great for the dark machinist world of Shadowrun to have some real eggs and bacon in the morning. The players could also barter with the homeless, giving them food instead of money and this could be even rarer and more valuable in their circles.