Sorry to hear about that. I would consider a bad crank to be end of a saw. Sometimes you win, sometimes you lose. I bought an 056 in pieces off ebay for $75. When I got it, it turned out to be an 056 Mag that just needed an ignition. Jug, piston, crank were perfect. Now I have a good saw that I regularly see sell for $300-$400.
Then, I bought a trimmer that was quite a bit rougher than advertised, but probably the seller could argue that it was fine. Oh well, I got it to run pretty well and I'll probably put a new piston in.
Ebay should give odds on getting screwed.
Chris B.