Start a new game, any year on Hard level, type "FUND" until your cash is at $60,000 (reply yes to all queries). Now go to the budget menu and select bond repayments. Then click on repay bond and answer yes to repay bond at 3%. You will now get $50,000 every year.
When you start a NEW game, before doing anything else, use the fund above cheat TWICE, then take out a regular bond (through the budget menu). I've had interest rates of -15000% with this cheat, so you'll get a few million each year.
When you have started a new city (in easy mode) take a loan. Go to the map and type "Found". Then go back and make another loan, and now you earn 1.5 million a year.
For a large amount of cash follow these steps:
If you don't have around $500,000 more cash in the funds, then redo the above steps exactly as described.
Try typing the following during the game:
"CASS" -- gives you $250 (after 30-50 times causes a firestorm)
"JOKE" - for a dumb joke
"VERS" ----- for version
"GUZZ" ------------- ???
"PIRN" ------------- ???
"ARDO" ------------- ???
"TOPS" ------------- ???