I should mention: with the increasing size of games, as well as the size of various things such as music and movies that will occupy a memory card, it's really best to physically purchase as many things as you can. With the current limits of everything involved with memory in regards to the Vita, you're unlikely to ever see memory cards for the Vita over 32GB, and for an active gamer, that won't ever be enough in this generation.
Edit: Alternatively, just start building a small collection of 16GB or 32GB cards. I'd imagine about five of the former, and maybe two to three of the latter would be good for just about anybody. I'd suggest waiting for memory prices to drop before stocking up though, otherwise you may be kicking yourself when you don't need to use another memory card that you purchased until they're only maybe two thirds of the price they once were.
Edit: Alternatively, just start building a small collection of 16GB or 32GB cards. I'd imagine about five of the former, and maybe two to three of the latter would be good for just about anybody. I'd suggest waiting for memory prices to drop before stocking up though, otherwise you may be kicking yourself when you don't need to use another memory card that you purchased until they're only maybe two thirds of the price they once were.