Years ago there were auction houses specialising in selling off business recycled PCs and bankrupt stock - it was great fun to go and mooch around and see if there was a real bargain not spotted, but they seemed to vanish under the onslaught of eBay and frankly for second hand tag I struggle to trust ebay
I’ve had good luck recently (sample size: 2) buying small form factor PCs off of ebay. Way more powerful than even a new raspberry pi, and a 4 core/16G RAM/256 ssd machine can be had for less than $60 if you are patient.
