I went to Best Buy to buy an iPad Pro and they didn't have any. Where else can I go to purchase one that isn't an Apple Store? The closest one to me is two hours away.
Well.... as you didn't tell us where in the world you want to buy, nobody can give you a direct answer. The best I can suggest is get online and search the likely suspects like Best Buy, see who /where they have stock near you. If you are sure about buying and don't need to check it out hands-on you could even order online from Apple and have it delivered to your door within a day or so.