I have a job where I drive around quite a bit. There are half a dozen thrift stores that I pass with some regularity, and a dozen more that I pass a few times a year.
When I have time, I stop in, and 90% of the time there is nothing (unless you like cool old weird clothes) but every once in a while there is a great Hawaiian silk shirt or interesting keyboard for $5 or less.
I have found a few Model Ms (all with some significant problem), numerous Apple Extendeds of various style, a Focus 2001, a Northgate Omnikey with a dead key, a non-working Cherry brown POS, some Microsoft Naturals (good old configuration) and the dreaded Milton-Bradley 101 Elderly/Educational.
Making an expedition for this purpose is not a good plan, but "just stopping by" in hopes of finding something 1 time out of 10 is much more realistic.
IMO
PS - I also live less than 5 miles from Rawko which is good