After you defeat Nelly in a drag race in event challenge mode, you will
get his Mazda RX-7. Keep repeating that race, and when you win you will
get over 100,000+ RP every time. Repeat this as many times as desired.
Easy Car Unlocking
While playing Racing Life, an easy way to
get new cars without buying them is to go back into races where you can
choose cars. Then, all you have to do is pick a car you don't have and
win with it.