It would be nice in city RPGs to start a business, and sell stocks. People could buy them and the amount of money the business has would be divided among the stock. The business owner could decide how much the stocks would be (%) of the company. Another person could even buy the company.
It would be nice if this came with a Object selling system, that the gun say was worth 100$. The salesperson would get 20% so he gets 20$, and the business gets 80.