I dos version:
Do this in the DOS version:
Start a new city, easy level.
Type FUND 5 times. Click "Yes" each time. Go to the budget and click the 
book next to BOND PAYMENTS, then press REPAY BOND 5 times. After that, 
click ISSUE BOND one time. (Never pay back this loan)
Now you'll get about 1.000.000$ each year!

Whatever version:

vers = shows your version
torg = gives you 500 000$
Do this:
Clean up a 3x3 square outside your town. Put a waterpump in the middle,
give it electricity, but NO water. Now your town will never complain about
not having enough water.