Start a race in career mode and type in goldfinger. If you entered it right you will hear a sound then type in givememoneyordie if you entered it right you will hear a sound one more time. Exit and you will have 1 million dollars.

In the level Farm Road 109, under the train bridge in the water there is treasure chest. Run over it and get free money.

Pass checkpoint 2, but continue forward instead of staying with the track. Go between two hangars and continue on across a small lake. Ahead of you will be an American flag. At the base of this is another hangar. A money box is next to the hangar.

Pass checkpoint 6 -- it is easiest to do a 180 at the start line. Go over the tracks over the mountains and find the little town that is out a bit.

To get a secret course go to the salvage wasteland. Do a 180 at the very beggining and plow through a gate that is there. Keep going until you come upon a road (it doesn't matter what way you go on it). Then a dirt road will come. Follow that. Then it will turn back into a paved road. Follow that and then there are jumps (the secret course).