They have the max to stop from people selling chicken for 1mil, and having some 1 else buy to transfer money to another account, or real world trade. However, the minimum doesn't do a thing. I think they should change the max to 10%, and remove the minimum. As like you said, I usually sell stuff dirt cheap to sell it quick. I don't want to sell it and have to wait for a buy, cause sometimes I need money that instant and not in 5 minutes.