Type "goldfinger" during game play. Then, type givememoneyordie. Exit the race and you will have $1 million. Repeating the code will set your current amount to $1 million -- you cannot get more than that amount.
To get more than $1 million, after using the goldfinger and givememoneyordie codes, buy the most expensive truck or SUV that you can. Spend all of your money on it for the most value. Then, return to the game and enable the goldfinger and givememoneyordie codes yet again. You will be at $1 million. Sell your vehicle to get over $1 million. Note: If you have more than $1 million and repeat the codes, you will lose your money and drop to exactly $1 million.