I can say, at least in government, that open source is almost entirely used as a cost-saving measure, but it’s implemented so poorly (by the time a piece of software makes it through the proper channels for verification, it’s already several major releases behind. Which explains why CentOS is still so prevalent) that the general opinion becomes “open-source is just a cheap substitute for a superior commercial product.”

A couple years ago my in-laws were downsizing after retiring and they asked if I would possibly have any use for their ancient desktop PC (at least old enough to have shipped with Windows 7).

I installed Debian on it and it’s running Jellyfin, qBittorrent through Gluetun, Calibre-web, NextCloud, and Pi-Hole containers, with plenty of room to spare. I’ve also got some services running on Raspberry pis (back when they were cheap). And an external 4TB hard drive connected to it acting as a NAS. No hardware transcoding or 4K video on Jellyfin but that’s no big deal for me.

All that to say yes, you can absolutely self-host on repurposed hardware. Any old PC you’re looking at is no doubt newer than mine.