The GBA game Mario and Luigi is one of the best GBA games. Really well written and a blast to play as an RPG. One of the best features I thought that made the game a lot of fun was I didn't have to do random battles to level up the Chacters. I don't think you need to play the first one to play the second but the first one is really good.
Mario Kart and Animal Crossing is $39.99 at RCSS also.