The best way to turn a profit doinf anything is to offer a product at a product that is the same or superior to others on the market, for less than it is being offered now. Typically dive shops are operated and maintained for the love of the diving alone. To revisit the raceing analogy, it will cost you everything you have, + 20%. The dive gear distributors/manufacturers are also way behind the times in their thinking. Their business model is based on exclusive brand loyalty, large upfront purchases, and the thought that the economy is fine,
good luck
Eric