the wife and i go to thrift stores about every weekend. she looks at her stuff, i look at mine. i'm usually done in about 5 minutes, she takes about 20. i might buy something 1% of the time.
anyway, the first thing i look at is the bicycle section. it's very rare that i find a bike i'm remotely interested in. 99.99999% of the time its kids bikes, and if there is an adult bike it's a huffy or a next or some other walmart bike. about a year ago i bought a 1980 schwinn le tour, made in america for $20. i put about $50 in it to get it road worthy. i didn't figure that was a bad little score.
this evening i happened to drive by a thrift store i frequent, so i stopped to see what they had. i was surprised to see they had a mens giant mountain bike that looked to be early to mid 90's and a trek mens mountian bike that looked to be late 80s, early 90's. i didn't make it as far as looking at the models. i don't know much about bikes, but i know trek and giant are fairly nice brands. they both needed the works, cables, housings, tires, tubes, grips, brakes, saddles, i'm sure the bearings needed cleaned and re-packed. i can do all the work myself, but they wanted $40 for each bike. i figured by the time i pay $40 each, buy all the parts, and do all the work i'd have more in them then what they're worth.
last week i found an old 70's bianchi road bike in another thrift store that also needed just about everything and they wanted $100.