-Once you unlock the moon track, make a race on "grudge race" mode. Once you win a race on the moon, the amount of your winnings will be multiplied by 10. For example, $20 becomes $200 and $600 becomes $6,000. Also, if you lose you will only lose the original amount, and not the bonus amount. You can use this at anytime after unlocking the Moon Drag track.
-Enable the SIMONE code unlock every car and receive $76,000. Then, sell as many cars as desired to receive more money. When you are done you will have money in the upper millions.
-Purchase your first car. Go into "Engine", "Body", and "Chassis". Sell all the individual parts by clicking "Remove". Do this for every category of the car then go back to the car selection screen and sell the frame. Depending on the vehicle you should make about $300 to $800 for each car. Do this enough times and you can then buy level 10 blocks. Once you make enough money you can keep a car with all the parts out and keep saving to fully upgrade the car by repeating the process. After about thirty cars you might have a 6.5 second hot rod in your garage.