To get even more money after enabling the "$10 million" code, whenever you go to the bars (especially in Greenback) play the slot machines on the left. They will always pay off.

When you go to the garage to trade trailers, buy a trailer extension so you can haul more product and make more money.

Unlock the "Max Fruit" cheat and enable it. Visit the bars (especially Greenback) for a $750,000 All Bars payoff.