Usenet was great back in the day. uk.adverts.computer, got a GF256 for 70UKP when they were new! Got a dual pentium, a CRT probably over 40" .... a Mitsubishi beast. Tried googling, but the modern web is too JS-to-view-images for me.
Bit more contemporary, https://www.used.ca/ operates here in the UK, and absolutely will in Canada, with lots of used$SHITTY_BRITISH_TOWN.co.uk sites. The local site for me has a constant flow of old corporate kit, but sometimes people selling more interesting stuff. This kind of site can end up with people shifting job-lots of stuff they don't know about, like a box of computer kit they've ended up with: a potential bargain.
Oh yeah, my local $SHITTY_TOWN site right now is full of spam for "research chemicals", and otherwise not much but corporate clearance in the computer section. I guess the proprietary markets are taking people? Like shit inside Facebook? I'm not about to remove the *facebook* filter from my adblock rules to try and find out 😀 Someone the other day suggested to me I look on Tiktok for a cheap/free laser printer /facepalm