Enter the following at the 'Press Start' screen:
All tracksDown, Down, Left, Right, Up, Left, Circle, R2 All carsUp, Right, Left, Right, Down, Up More money Up, Left, Left, Right, Down, Right, L1, Square
The Hard Way:
The only way to get free cars is to win first place in every race. Also to get the team cars like the Mosler Raptor, Team Mosler, do the above plus you need enough cash to do the special race.(Head to head)
Thanks to Revolution readers Martin Brody, Corey Zick, JeremiahDavisY2K and Glass Joe!