Coins and Stamps business. Business Overview Opening a retail store that buys, sells, and trades collectable coins and stamps is a good business venture for the hobbyist coin and stamp collector to get going. The store does not need a great amount of square footage, as the inventory is compact. As a method to reduce start-up and operating costs, consider a joint venture with another retailer. Good matches for this type of shared retail space include pawnshops, comic book...