Big heads:
Hold L and quickly press B, A, B, Y during game play.
Big chests:
Hold L and quickly press B, Up(2), B, Y during game play.
All characters and costumes:
Select exhibition mode. Then, hold L and quickly press Left, White, Right, White at the character selection screen. A sound will confirm correct code entry. All characters and costumes will be unlocked in exhibition mode.
Free Fight Token:
If you dont have a Fight Token, in Exhibition Mode, hold L and press White, White, White