A 22 and a 45 are the best start point. If you buy quality and look after it, you will always be in a good position to trade up as well.
Then a 357 for a wheelgun, a 32 seecamp for your vest pocket, a couple of shotguns, a 30.06, a 30.30 and then you can start thinking about the luxuries like reloading gear and exotics like a 22 remington jetfire and a custom built racegun