BEFORE you spend any money, down load the SASS manuals, find out which category that you are interested in. Some categories require specific firearms, specific belt & holster, specific ammunition, specific clothing. Spend your money only ONCE, spend it wisely. After you have read the manuals attend a couple of matches, ask questions, after the stages are finished for the day, ask people if you can try some of their gear. Cowboys are a friendly bunch, and many will offer their firearms to try. By reading the manuals first, your questions will always be more well thought out and the responses you want will better answer your questions. Asking what is the best revolver/rifle/shotgun depends largely which category you choose. Without knowing the category, asking the question which is the best firearm is a waste of time.
Also keep in mind that not all clubs are affiliated with SASS, but most pay lip service to their safety rules. Personally, for your first choice of leather you buy once you have your category chosen, I would not spend the family fortune at the beginning. Most shooters getting into the sport after a couple of matches decide that their original choices don't suit their personal style of shooting.