When possible, use coupons, discounts or buy in large lots to save money on what you sell. I have seen many clothing sellers who routinely comb the discount ladies clothing stores to find great merchandise on sale. Each penny saved on the purchase is more profit at the end. Buy in lots (more than one item per auction), if you routinely go to auctions and they have an interesting box lot – buy the box lot if there are one or two treasures you are sure will make at least the money you spent on the box lot back for you. Then the sale of other items becomes pure profit.