Build a sand bag and move the unit as close to the sand bag as you can. Click on the sellbutton. Move the cursor over to the sand bag. Move the twirling dollar sign as faraway from the sand bag and toward the unit as you can. While its spinning near theunit click to sell him.
If you put a vehicle on the repair pad (no infantry, of course), click sell, and movethe cursor over the unit, a little green $ will appear. You can sell the unit forhalf-price.
Infinite Minigunner
This cheat is called the Infinite Minigunner cheat: Sell any building, but before theselling animation sequence is over stop the sell, the building remains on its place, butall your minigunners are out.
Easy Money
This is more of a bug than a cheat, but it works. When you sell three refineries rightafter each other, the money you get keeps going up till the end of the mission.You can get as much as $20,000,000 if you're lucky.