Run over obstacles (such as beams on construction sites and wooden fences) to get extra money. Additionally, try not to finish in last place. You still get bonus money if you are in fourth through seventh place.

Start Career mode and buy the Grinder (the third or fourth car that looks like a Mustang). Complete about half the races in the Bronze class. Upgrade your car with the money you have, then go to the Bonus class races and select the High Jump. When you start, go down the ramp and over the first hill/jump as fast as you can; but do not hit the nitro/launch yet. As soon as you land off the first hill, hold Nitro to charge up as you go up the second and final ramp. At the top, let go. If done correctly, your driver should fly very high and over the top of the whole ladder thing in front of you, and perhaps even over the net that is supposed to catch you. This is the best combination of car and technique to score huge in this challenge. For some reason you cannot do this with the faster cars that are unlocked later. Keep your Grinder a little bit longer after completing the Bronze class and earn as much money as you can by doing the High Jump stunt challenge.

Buy any car desired when starting Career mode and complete the Bronze class events. However, do not spend too much on your car and try to save at least $4,000 to 5,000 dollars by doing so. You will earn about $4,000 upon completion of the Bronze class if you do well. Completing the Bronze class will also unlock new cars. Go to the car dealer and buy the Road King or a better car if desired. Once you do, go to the Bonus Events and enter the Oval Ring thing (the second one down on the far right column). This is simple race against other drivers where you drive as fast as you can around a big dirt oval. When the race starts, break away from the pack and just hold down the gas. Drive around the ring as smoothly as you can, avoiding the occasional stack of tires and junk on the side of the track. You do not need to smash through it because earning a nitro boost here is pretty much useless, and will only get you into a wreck by using it. Just stay in first as the other drivers muck about behind you plowing through rubble and smashing into each other. When you cross the finish line first after eight laps you will receive an easy $1,500. Keep doing this to earn money to upgrade your car faster and get an edge over the competition in the real races.