I got the bike free from a friend a couple years ago. Blew a crank seal while tuning it and then found the frame was tweaked. Same friend spotted an F11 hulk at another a local dirt track and I picked it up for $100, good frame, wheels and partial motor.
It was a lot of time, but the budget was nearly nothing. With the rattle cans, title, plate, tires, piston, bars, grips, battery eliminator, gaskets and seals, etc I'm probably in it for $450 to $500.
Have a set of motard wheels mocked up that I need to finish. It still needs turn signals, a seat cover, air box rubber and a few other odds and ends, but it is running pretty good.
This one will stay under $750 for sure