There are no official "money cheats" (invincibility/infinite studs codes) for Lego Star Wars II: The Original Trilogy on PS2. Cheat devices (Action Replay, GameShark) can corrupt saves. Instead, use these intended game mechanics to farm studs efficiently:
Bottom Line: The game is designed around stud collection as progression. "Cheating" bypasses the core loop; the Red Brick multipliers are the intended "cheat codes" rewarding exploration.