When you unlock the pagani zonda (best car in the game) it is for sale at $741,000 if u want it put in the cheat unlockallthings and do a race then go to your garage and u will have extra cars, sell them all you should get aroundd $100,000 for all of them. Save the game and reset your PS2 and then do this angain untill u have enough to buy the zonda, this should take
you 8 times but it can take less depending on how much money you already have.