Mike,

$97?
You've got to be kidding!
$97 is for something worthless.

"Warmer" points.
1.Love for cars is enough.
2.Don't promise. The benefits of the solution should be evident to any party involved.
3.Some message(s) should definitely be emblazoned on the car.
4.There should be a huge gathering of people.
5. You "can't afford"? THEY can't afford NOT "supplying" the cars.

Hints:
Barnum did "this".
Bernays did "this".
The solution is a win-win-win-win... thing.

Simon