Obviously you're not viewing this in person but is this a deal killer? It looks pretty minor to me but I don't know. It's an 80's 12 string going for $200. I actually have the same era though slightly different model guitar and and I love it so much I want another. Tks!
We have no idea what guitar you have other than what kind of guitar you have (80's 12-string acoustic). So valuing whether $200 is a good deal is a bit harder to do. Traditionally, a Gibson is much more valuable, then say a Samick, even if they are identically constructed.
When I looked at the blown up picture, I did see where the binding met (off center) at the back of the guitar. That is not actually a crack at all, and just a detail error in the manufacturing (as you can see, it seems to be filled with something a bit darker than the white binding):
If you're speaking about the finish variation between the strap-button area of the neck and the body that's also pretty common. Too much movement (that one would be worried about) would cause a physical separation between the body and neck here, not just some weird checking of the finish. Keep in mind a 12-string guitar is under about 2x as much string tension.
Seems like a stable guitar, and worth whatever you think it's worth, until we can get an average used value for what this guitar is (Who makes it, what model, what year, etc).
I'm not seeing a crack in the photo attached. However the price and age of the instrument, combined with the fact that it is a 12 string, would make me wary of entering any deal, crack or not. 12 strings carry a lot of tension in the strings, so watch out for the top warping around the bridge. This could be rectified by shaving down the saddle to compensate for any increase in string action over time, but a neck reset (the ultimate solution) is an expensive fix for a cheap guitar. The crack may well be simply in the finish, or indicative of structural issues that would cost more to fix than the value of the instrument.
While you might own and enjoy similar guitar, but you don't yet own this guitar. Evaluate it for what it is; a cheap, ~30 year old 12 string guitar.
I kind of agree with answer #3 It really depend on who made it as far as if its a good deal I dont see the crack at the heel but there would be more pressure there from a 12 string. any crack can be repaired if done correctly as to weather its a crack in the finish or wood does make a differance you circle shows the binding not touching but I dont see the crack I would say make sure the guitar is worth more than the asking price any repair by a luthier will cost a minimum 100..00