This glitch allows u to get cash instantly. If u want alot of money fast build a really expensive car. So after u have made a car and it's on the car lot u have to:
Tap the car
Buy all the upgrades
Put the car at the lowest price
Tap OK but make sure when u tap OK quickly tap the same car again (or just when someone loves it)
Once you're in the car options again tap the up arrow so that the car is at the highest price
Then tap OK for the last time
And once u have done all this tap the car one more time to sell it.
Try to alternate between completing Quests and straight up making money, as you'll need good reserves of cheddar to complete the timed missions quickly.
Occasionally, you'll see a very fast moving blur tear past the screen. Try to catch it.
At times, you'll see a chap with a camera in the windows of the factory. Tap on him for a bonus.