(FORTUNE Small Business) – Steve Mack traded in his family's 48-store chain of pawnshops to Fort Worth--based Cash America for $125 million in cash and stock. Mack, 46, started managing his father's single Reno location in 1981. He eventually modernized the family business by developing specialized software that enabled SuperPawn to auction items on eBay cheaply, catapulting the company to No. 5 on eBay's top sellers list in 2002. "Our average operating costs went from $20 per item to less than 25 cents per item overnight," says Mack, who has started a new company, Ztradingindustries, which will sell the software to other eBay vendors. — L.G.