Thrift stores are one rung on the ladder below yard sales. The stuff that doesn't sell at the yard sales gets carted off to the thrift store. So, for the most part, the stuff is pretty suspect when it arrives. Then, let it hang around on the shelves for a while for clueless "customers" to play around with and break, and, well, I guess one just shouldn't expect too much. Still doesn't hurt to look around, though. If I'm feeling bored and don't have anything better to do.
There's a thrift store about a block from my house. My wife loves the place, cuz she finds clothes there with tags still on for maybe a couple of bucks per item. Found me a really nice leather jacket that is now my favorite motorcycle jacket. It cost $40, but was at least $200 new. Great shape, too. While waiting for her one day, I looked through every non-clothing item they had there. No photo gear. They had a busted HP scanner though that would prolly sell in working condition on eBay for $20. Maybe. I found a five-CD set of the Pimsleur method for Chinese, though. That was a good deal for $5. (I paid over $200 for a Pimsleur method Chinese course on cassette about fifteen years ago). Still don't speak Chinese very well, but it isn't for a lack of instructional materials. But no photo gear, unless busted old Polaroid cameras count.
Best,
Michael