If you need some cash and you don't want to mess up your car you can just steal someone elses.
Instead of using one of the cars you have earned, walk out into traffic (traffic will stop) or find a parked car, press the Action key to get in.
Then simply crash the car until it explodes, and you will get coins when it does. If you want to do it quicker use your car to crash into other cars to blow both up and get even more coins. I suggest finding a schoolbus on level 1 they are nice and big and do lots of damage.
Taxis work well too because there are just so many, you trash one and wait for the next car to roll by.
Added by: mclapsadl Apr 28th 2004, ID#4534