I wrote my car off a few years ago, (skidded on ice, landed in some traffic lights, not completly my fault), the damage was literally bodywork, told my insurance company at the time that I wanted to buy the car back and get it repaired myself.
Took quite abit of pursuasion, spoke to the fella who checked the car over (for the insurance company) and was told the list of parts I needed to find, because of the age of the car ('93, but only had 40,000 on the clock) he put it down as cat D.
Bought it back for £100, the parts came through at a few hundred, and labour about the same. It worked out that I paid out what the insurance company gave me for the accident.
There is a site that sends an email out with all your parts on and if anyone (scrappies) have them then they contact you.
For me, because my car wasn't really very common, my seconds came from a scrappy in london! But I've had my car 3 and a half years since the accident, and had I spent that money on getting another 2nd hand car, it would never have lasted me this long!