If  the council is giving you to many blackmarks, build a level 2
house,  and  select  the  tennants  "the punks". After a while, the'll
start complaining about the fence. Decrease their rent drastically, or
choose  them  to  have  babies.  Now  you'll receive some white marks.
Repeat  this method, and you'll receive many white marks, which can be
exchanged for money.

The following codes only work in the DOS version.

     To activate, go to the player selection screen. Type in the codes
exactly as they are shown below, and press ENTER. If they were entered
correctly,  you will hear a beep. Enter the game and press C. A + sign
will appear next to the date if the cheats are active.

speed471                Network play speeded up 
worker902               Buy a worker at any time 
gangster822             Convert workers into gangsters
weapons473              Buy any weapon for the gangstera
tenants127              Select any tenent at any time
fences673               Build any fence at any time
loans039                Borrow any amount of money from the bank
estates131              Buy any estate
houses738               Select any house at any time
build909                CTRL becomes a hotkey to build instant houses
actions674              Use all undesirable actions on easy level
gadgets337              Build every gadget
missions824             ALT + I becomes missions toggle
complain840             Turn complaints off by pressing ALT + C
teams418                Change teams in single player mode 
map751                  Play any map with any number of players  
cadets552               Bribe police cadets (press ALT + P) 
                        and bribe the mob (press ALT + M)