Go to main menu and load up your game, then pause the game and hold down LB, RB, LT and RT all at the same time. A note will come up, select 'Yes, I understand. Let the cheating begin'.

When you've done that, go on to build and buy mode and buy. Go to miscellaneous decor and pick 'Spoot the Magic Llama'. It costs $0. Place it anywhere and go to live mode.

Click on the Magic Llama and it will come up with loads of cheats.

Every cheat can be used more than once, and you can use the Magic Llama as much as you like!