You are not just asking for a name but something like a monetary system? or a way the in-game economy works? I got it wrong?
If not. Then what about a 'favor-based' system? IDK if your game has secondary missions or mini-tasks, mini games. It could de something like: You have a 'board' of secondary missions or tasks that in exchange they provide a reward (the item you normally would buy). Or, If you have secondary characters it could be something like 'favorxfavor' something like: you (the player) do something for them, in exchange you are allowed to ask something return. Or just barter. But instead of solving every items value to a monetary equivalent (like fallout does making all items has a certain value of caps) you can make that each character values different items in different way. You could have a blacksmith that values more the iron blocks and health potions instead of the weapons, or a gnome that values more elf's hair than gold, and so on.