Cash for non-functioning vehicles, towing included

The financial incentives offered will have to be market-rate.

of financial incentive and little/no effort for participants

This could work but probably a lot of paperwork as you’d need to validate that the vehicle being towed is yours. Also I believe the amount of cash provided would need to be not so much that people wouldn’t attempt to repair their car if it’s possible. It might be too complicated to implement effectively.