Learn how to unlock skills:
Super Saiyan 3 Goku: defeat Fat Buu the first time you see him with Goku
Babidi's Mind Control: defeat Majin Vegeta with any character the first time you see him
Red Ribbon Base: get 50,000 zenie then go to the skill shop and at the very bottom is Red Ribbon Base
Babidi's Space Ship: complete the game and have all the dragonBalls, then wish for Babidi's space ship where you can get Dabura, Fat Buu, Super Buu, Kid Buu