I just refinished my headlights on two vehicles with this kit:
The results are OUTSTANDING! The process uses an electric drill and a spray bottle with plain water. Took less than an hour to do both cars. The kit comes with 2 refinishing pads...I did all 4 headlights with 1 pad, so it's possible you could do 3 or 4 cars with one kit. You would just have to do all the prep on all the cars first and then "polish" all of the cars last.
I HIGHLY recommend this product to anyone with cloudy headlights.