Money Cheat:

First buy any property that has garage. Then get A police car.
Drive the car to your garage. Start the vigilante mission.
Get out of the car. You will be give 60 seconds to return to a
police vehicle. Get out of the garage. When the garage door closes
type the cheat "BIGBANG". All nearby vehicles including the criminals
vehicle will blast. And the vehicle you stored in the garage will be
auto repaired. Then you will get a reward of 50 bucks. Then again
enter the car that you stored in the garage. Again get out of the car.
Again get out of the garage. Type in "BIGBANG". Again the threat will
be eliminated. You could do this as many times as you like.