How many gb are on a playstation vita game?

In addition to what everyone else has said about how much those cards can hold you also must remember that they won't be the same size games in the ps3 as the vita. The PS3 offers 1080p 1920x1080 Resolution graphics, surround sound, and a bunch of other crap. PSVita will have less pixels (smaller screen) saving a considerable amount of space, as well as only stereo sound (no big surround sound files) In addition to this, compression of the game will also play a huge factor, since you can compress games to be only a couple GB's.