The cheat "iamcheat" and his friends only work with the Win95 versions. GoG offers the MS-DOS Version. But if you are in trouble with your balance you can use an easy glitch to get a lot of money every year:
1. At the beginning of a new city, type in FUND and click on YES.
2. Type FUND again and click on YES.
3. Open the Window menu and select BUDGET.
4. To the right of Bond Payments, you will see an open book icon. Click on it.
5. Select the button ISSUE BOND and click on YES.
6. Select the REPAY BOND button to repay the first bond.
7. Select the button ISSUE BOND and click on YES.
8. Select the REPAY BOND button to repay the second bond.
9. Select the button ISSUE BOND and click on YES.
10. Don't ever repay this bond. This will give you $1.4 million every year.
Or the short version:
1. Take 2 bonds by typing "fund"
2. Open your budget menu, open the bond section, take a third bond (you will see that it is ".%") and repay the first 2 bonds (just repay 2 times).