The 1/72ish scale figures I’m now using for Deathzap are a good match for your standard discount shop toy cars. Destroyed civilian vehicles aren’t often something you see on a gaming table but I think they add a lot, they take a set up from an arena for doing battle to a place people actually used to live and work in.
Most of your cheap toy cars are of a sports variety and have a sci-fi ish look to them which is perfect for my purposes.
Turning a fresh car into a wreck is fairly easy. Don’t bother repainting the car like so many do, the manufacturer already did that for you. Instead attack it with a drill (for bullet holes) and a file to chip off paint and add scratches. Then get your wife who has a sadistic love of smashing things to hit it a few times with a hammer.
The final step is to use cheap black acrylic paint to coat the car and then before it dries rub the majority of the paint off with a cloth.
As I said I think a few wrecks make a big difference:
One of the cars was a little too damaged for use and was showing off the lack of detail on the inside. To fix this I shoved clump foliage into the gap and set it hard with super glue. I then drybrushed it up to look like fire, I’m really happy with the effect:
Deathzap 
Love it, but I guess which vehicles you use depends on how you imagine your worlds. Personally I’d add a few battered buses & trucks!
As soon as I find some that look appropriate I’ll definitely be adding those too. I’m also on the hunt for other common street furniture, benches, bins, dumpsters, street lights etc.
Love the burning purple car.
Regards, Chris.
Great idea, especially the burning wreck, which looks great.