Copy Items and Money;Start a two player game then press Start and select "Add/Remove Player." Import your first character to the player two slot. Player 2 will now have a copy of your inventory which you can sell. Repeat as necessary.
Double the Fun:Make a duplicate of yourself at any point during the game to create a decoy. This works especially well during boss fights.
Lots of Experience:If you want to do this you must be sure you have room for two savegames on your memory card.
When you get to the Final Act, after you free Fironia you cannot enter the halls of Despair anymore. Save your game before you rescue Fironia and you can return there anytime, by importing your characters into the game. You can keep gaining exp, and also good equipment
Save exploit: Make sure you have room on your memory card for more than one save. The idea behind the cheat is to import your own character into a map you control. So, if you are after experience fight your way through the game to a boss fight with an easily accessible save point. Fight the boss down to the last hit and then withdraw to the save point. Save the game, this will be the map reference. Now, go ahead and wander back towards the boss and kill him. You gain the xp and loot of the boss fight. Return to the save point and save your game on < Create New Save Game >. This will create a new save that we'll use to import from. Now, exit the game and reload your map reference save (1st save). Once inside your game, hit start and go to Add/Remove Players... Highlight your own character and hit triangle to import a character. Import your character that already has the boss experience into the map reference save you created and you now have the opportunity to kill the boss again (in one blow no less) and regain his xp and loot.
Alternate exploit: Utilizing the save method, you can effectively farm cash and items through item duplication. Drop the item on the ground you want duplicated from your map reference save and then import your character. Pick up the item and you now have 2, update your map reference save and then drop both items now. Import your character and pick up both items and you now have 4 of this item. This growth is exponential and over time will amount to insane amounts of cash if your selling, or you can duplicate your favorite weapon to dual wield, or just duplicate augmentations to slot into your armor.
NOTE: on the alternate exploit it is only necessary to have 1 save spot available
Ultimate Levelling Cheat:Get to the Boss in the Tower of Clouds (The giant that's right before talking to Lazlo) and Beat him down until he has about 1 or 2 hits until death then press start, go to add and remove players and make a new character that you want to level really fast. After he/she is created, press start and remove your old character from the game, (You probably want to save before doing this). Get the last few hits in with your newly created level 1 character and your level will jump accordingly: on the Adventurous difficulty you'll get level 15 with all stat points and skill points for up to that level. On the Courageous difficulty you'll get level 36. If anyone does this on the Champion difficulty, post your results.
Level 20 character and 999 skill points:
When you begin playing the game after you have created your character and you gain control of them, enter this code during gameplay: Press and hold L1, R2, Triangle, R3. Your character should say something and you will now have a level 20 character and 999 skill points.
Defeat Cloud Giant:
Go to the left or right and hide behind the fire where the cloud giant cant get you and fire arrows attacking between 50 and 70 damage. I used over 150 arrows.
This is ratherly a simple trick to preform. Espcially with multi-player games that allow import of other characters. You will need 1 empty slot in your memory card for this to work. Take the character that holds the item(s) you wish to duplicate. Save it to slot 1. Then go into your inventory and remove the item(s) you wish to be duplicated. Drop them onto the ground. Then hit start and go to Add/Remove Characters. Once you are in that screen hit 'triangle' to import another character. You will be takened to the screen where all games are saved. Chose the game which you just saved in. Select the game, then the correct character you wish to import. Then after the loading screen finnishes, you will be standing on/near the item you previously dropped. And if you look in your inventory, you will have the same item in there. Pick the dropped item up and save your game again. Keep repeating until you are satsified with the amount of duplicates. Great way to get rich, is by duplicating items that sell for tons of gold!