While not a "thrift store" find, I did recently get a terrific bargain on a Zeiss Milvus ZF 85mm f/1.4 lens on Ebay.
First, you should know that I have experience repairing/adapting/building lenses.
I found a Zeiss Milvus lens in the Nikon ZF mount on ebay. It had damage to the rear of the lens and was being sold "for parts".
I bought it for $400 USD. When I received it looked like someone had either: thrown the lens against a hard object, dropped it off of a tall building, or the rear of the lens had been run over by some type of vehicle. The glass and focus ring were perfect, but the mount and aperture were "rough". It's a tribute to the design and build of Zeiss Milvus lenses that this lens could take such terrific abuse and still have it's glass remain in perfect condition!
I was able to fix it enough so that it would mount perfectly on my camera. There were parts missing/damaged that controlled the aperture; so the only way I could change the aperture was to disassemble the rear of the lens.
So, I set the aperture to f/2 (which is what I shoot 85mm lenses at most of the time) and just leave it there.
Now I've got an $1800 85mm Zeiss Milvus lens that I bought for $400 that works great (but only at f/2) !
Look for bargain cameras and lenses that are being sold "for parts". Sometimes the repair is easy (or cheap) and you can turn the broken camera/lens into a good shooter and save yourself big money. Basic lens repair can be learned by watching YouTube videos, and you can do lots of repairs with just a cheap spanner wrench and a 5 Euro Irazola philips screwdriver (
http://www.leitax.com/Zeiss-Contax-lens-for-Nikon-cameras.html).
