Ok, for easy money go to Gran Turismo mode, go to Special Condition Events with about a 276 hp car. You'll see the list of events, if you do the first one, you'll win a Cadillac Cien; it has about 640 hp. You can't sell it, but it is fast and you can use it to win the next event. Back on the list of events, go to the second one with your Cien. Win those two races and you'll get a Toyota RSC Rally car; this is the one you can sell. It has about 463 hp, I think. When you sell this one you get about 250,000$ or more. Still, it's a lot of money.
Hope this helps!!!
Added by: Pepperfoot Jun 11th 2008, ID#30299