Unlock Cheats:
During gameplay press-up, triangle, down, X, left, O, right, square. You should see a message that says cheats unlocked. Now you can enter a code below:

Super Bounce:
During game play press- left, square, X, up, triangle.

Super Bunny-hop:
During game play press- up, X, left, square, up.

Anti-Gravity:
During game play press- down, triangle, square, square, up.

Mega Flip:
During game play press- right, up, up, right, right, square.

Combat Upgrade:
During game play press- up, down, left, left, right.

Energy Restore:
During game play press- down, right, right, left, left.

Adrenaline Boost:
During game play press- down, left, , left, right.

Upgrade to Bottle:
During game play press- up, down, left, left, right, right

Stoke Trick Meter:
During game play press- down, left, left, right, right

Combat Mode:
During game play press- Left, Square, Circle, Square, Left

Get ,000:
During game play press- Right, Up, Up, Circle, Circle, Square

Hints:
Go through the Black Diamond gates(follow them in a row) to earn a little extra cash.
Punch, kick, check, throww bottles and whack opponents with a stick to earn more cash.

Easy Money:
Go to 2 player and do a single event (it doesn't matter if you have a second player or not). Choose any rider and course. Do the race but make sure you don't get 1st place. Make sure that the second player doesn't cross the finish line. Then just beat everybody up that's there with your attack and once you think you have enough combat points just get the second player to the finish.