7-Eleven Inc., the convenience store giant, on Wednesday put all 475 of its company-owned stores in Florida — including 88 in the Tampa Bay area — up for sale to franchisees. It's one of the last states in the 5,400-store network being converted to a franchise-only organization. Store managers were offered first rights to acquire their store. The average investment is about $180,000 for the business and inventory but excludes the real estate. Unlike most franchises, which pay a percentage of sales royalties, 7-Eleven splits the profits. 7-Eleven is making the switch to foster more entrepreneurial managers and provide owners closer to their community.