Custom Game
Note: This procedure involves editing a game file; create a backup copy of the file before proceeding. Use a text editor to edit the "c3_model" file in the game directory. By editing this file, the cost of objects may be changed (lower or free), improve desirability, and lower the number of people a building employs.
Don't Pay
While building street, plaza, gardens, etc., put where you want to end building close to the right build buttons. Hold down the mouse while you are building a street, etc. and drag the mouse off the screen onto one of the build buttons. Your money stays the same. You must build one thing for real before you use the north, south, east, west buttons or it will become disfigured. Works great on streets, plazas, gardens, but not houses.
More money
Need more money? Want to skip a certain mission? Then here you go!
In order to enable the cheats you must right click on a Well, then press ALT K. Now, to achieve instant victory, hit ALT V. To give yourself more money, hit ALT C (this will only work if you have less than 5,000 DN).