Not a friend, nor a chainsaw. I picked up a walk behind trimmer last weekend. Thing had been sitting for several years, inside thankfully, and was so covered in dirt and grime you couldn't tell what brand or anything. Got it home and took the pressure washer to it, only to find a nearly new DR pro, complete with electric start and being self propelled, $1000 plus trimmer, and I picked it up for $10, because it was "broke". Little gas in the tank, and it fired right up, couldn't believe my luck, then I got started going over it, and I figured out why it had been sitting.
Apparently the owner decided he didn't like the self propel, maybe it was too fast, who knows. Anyway, he apparently decided to disable it, and instead of just removing the belt, he had taken the pulley off the transmission, and drilled the center out, put it back on, and put the belt back on. So now it flopped around uselessly, and the belt inevitably had come off and wadded up like a ball around the belt for the head. He had also took the drive chain off, but left it dangling around the two axles. And of course instead of getting his $1k trimmer fixed, he just parked it and bought something else.
Just further proof some people have more money than they have sense.