I got mine non-working for $170.
It was board issues though, PS needed new bridges and some sockets on the game board had to be replaced. IF it's just a pully issue, then that'd be even better.
I wouldn't go over $200... I lucked out on mine and kept bidding (real life auction)... I went over my "limit" by $10, and luckily the guy I was bidding against, I guess, had the same limit... because he finally stopped and I won.
That's in an auction environment... so YMMV. Check with him to see what the issue is, if the game keeps resetting... probably a socket issue like mine was (I hope). If it resets without a thud sound, then there could be a bridge issue too (Radio Shack, amazingly enough, carries bridges that will work)... board issues are harder than stringing some weed-eater line up to make the pullies work. If the thing is completely dead in the water... no idea. Check with him to see exactly how "non-working" it is... if the pullys just keep pulling (not finding their limits)... simple switch or chip replacement.
Personally, I love mine... but I went WELL over my $50 limit for non-working games for this one... and I'm really happy I did.
Remember though, if it is a board issue... they are really simple... no video shit, no VRAM shit... no nothing like that. Anyone that does board work, and has one of these, should be (SHOULD BE, I'm probably the exception and just REALLY lucked out) able to fix it in no time assuming the all the chips aren't rusted to bits.
It's all your call. If you can get him down to around $200 (or as your budget allows, and depending on the shape of the playfield/glass)... I'd get it. It's a weird game... not as rare as some, but not nearly as common as most... but still fun as hell (IMHO)... so it's all your call.