In the line of the last suggestion, lets imagine we pay 40Tokens for a item that is available in the shop, so if we send to someone else because we have a deal, the price will rise to 80T so+40T

Second time we add 40T which is the base price so, 120T

A third item movement would be 160 and a 4th or more item movement would keep the price to 200Tokens that would be the max. Maybe we could allow to add money to get the item, so to have a better deal.