Extra money
Pause the game, then hold L1 + L2 and press Left, Left, Up, Down(2), Up, Square. If you entered the code correctly, you will hear a sound.

More store items
Pause the game, then press L1, R1, L1, R1, R2(2), Triangle. If you entered the code correctly, you will hear a sound.

All characters
Enter the character customization screen and highlight the "Name Selection" option. Quickly press L1, R1, R2, L2, L1, R1, R2, L2, Square. Press Left or Right to select a new character

Restore health
Pause the game, then hold L1 + R1 and press Down, Up, Right, Left, Down, Up, Square. If you entered the code correctly, you will hear a sound.

Restore stamina
Pause the game, then hold L2 + R2 and press Right, Left, Right, Left, Down(2), Square. If you entered the code correctly, you will hear a sound