From the main menu click options and then go to Cheats and enter these.
Code                    Effect
GIEVEPIX                All cars and 1 million creds
GIVEALL                 All tracks
WOTKINS                 Flatmobile car
RAIDERS                 Ice Cream Truck
RUTTO                   Pimpster car
KALJAKOPPA              Rocket car
GIEVCARPLZ              School bus