Last Macs I got from a thrift shop were my IIci and my SE Superdrive, at $20 each 10 years ago, most others came from my old high school 10-15 years back, or the local recycle center buyack shops... Unfortunately most old computers are now ungloriously categorised as "e-waste" and money stands to be made from the copper, gold and lead recovered from them, so there are now companies contracted to scrap old gear that goes into landfill, as it is more lucrative than hoping to onsell to the public. I used to work at a thrift store a couple of days a week to fill in time when my job was slow back in around 2012 and even by that time, they didnt even accept computer equipment anymore, and whatever was dumped out the back that i didnt find was taken to the local privately-owned tech-waste center. I squarely point the finger at these enterprises as the major reason that vintage or older computer equipment is basically non-existant on the secondhand market now.