Go to the game diretory. Go to sandbox. There is a long list of all the maps.
Go to anyone of them (you can come back and do otherones). Find [FUNDS]in front
of it its going to show a number. Change that number to any number you'd like. 
(Note: You have to save any edits and that goes with my other cheat submits). 
(Another note: The cheats will only work if you start a new game). 
When you open a new game with the map that you edited. 
It should have a lot of money.