Contact a local junk yard, automobile dealer, or auto insurance company
to see if they have a car in relatively good condition (just the body
and glass) that they would be willing to donate to your group. All
fluids should be removed from the car as well as other hazardous
materials. Allow people to take a swing at the car with a hammer for
$2. Proper safety precautions must be taken such as safety glasses,
protective outerwear, and a safe distance maintained by the crowd. Have
paramedics on hand in case of emergency and check with your local
authorities for permission and other safety tips. Contact your local
rescue squad to see if they would be willing to give a Jaws of Life
demonstration. This should bring in a larger crowd and more people to
pay to smash the car.
You could also consider smashing the old playground equipment in this way!