You never know what will turn up in Thrift stores. I haven't really dug deep through them with any regularity in the past 10 years, things that interested me seemed to get more sparse, and the internet took up the slack (ebay, etc).
For that stuff to turn up at a thrift store, it would have to be someone dumping something they don't know the value of, due to that person not knowing or it being a person's "estate" being dumped.
Even once it gets to a thrift store, a lot of stuff seems to get checked by those thrift stores, against prices online, and if it's something of a certain value, placed on that goodwill's auction site, ebay, etc.
Sometimes things slip through. For example, this year I purchased a book from a long dead author for $4 shipped. I examined the book when it arrived, and it turns out the book had an actual autograph inside it. I guess the goodwill missed that. Whomever donated it, they must have missed/forgotten about it, or it was part of someone's book collection being dumped by relative/whomever.
I'm keeping the book, but it's interesting to know I ended up with a book I could get at least $100 for, for only $4.
*edited to add;
Probably, better for finding this stuff in the wild now, would be yard sales, estate sales, and though it's now on TV, storage lockers. There was a particular member here, years ago, ended up with a locker full of new Sega CD, 32X games and such, due to a storage locker.
In the very late 90s, I want to say 1998 or 1999, before ebay really took off, I found quadrun for the Atari 2600, cart only, in the wild. It was an old guy, selling misc stuff at a community flea market. He had a box of Atari 2600 stuff. Leftover from his son who went to college, then away on his own. It was a good price, so I bought the box of system and games.
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