You mentioned that you wanted to start a tank. Now you are talking about your store not having what you want. Is your tank already set up and cycled? If not, then that needs to happen before you even think of adding fish.
During the month, or so, that you are cycling, check with your store and see if they can order what you want. Every store that I have ever dealt with has offered to order what I want. Even PetCo, which kinda shocked me.
For fish, you should figure out what you want and then add in the order suggested. Ask here and people will help you out. Don't rush into things. Saltwater requires patience. Lack of that will cause you troubles (and money).