During gameplay, hold CTRL and then type "hdicash" to add money to your account.

Cheat List:
Hold CTRL while playing on the main screen to enter the following cheats:

hditech - Complete current research
hdilore - All technology
hdizooma - Unlimited zoom on/off
hdidizzy - Use ALT, UP, DOWN to control camera
hdiart - View animation data
hdirate - Add 40 to mall rating
hdicash - Accrue $100,000
hdimax - Editor on/off