I’ve never done any sort of home networking or self-hosting of any kind but thanks to Jellyfin and Mastodon I’ve become interested in the idea. As I understand it, physical servers (“bare metal” correct?) are PCs intended for data storing and hosting services instead of being used as a daily driver like my desktop. From my (admittedly) limited research, dedicated servers are a bit expensive. However, it seems that you can convert an old PC and even laptop into a server (examples here and here). But should I use that or are there dedicated servers at “affordable” price points. Since is this is first experience with self-hosting, which would be a better route to take?
You could ask the question for video gaming. Can a used computer do the job? Yes, but you may not be able to play cutting edge / demanding games if your computer lacks the appropriate hardware. It really depends what kind of things you want to do, for choosing hardware that’s powerful enough.
Jellyfin? You need to consider if you need transcoding. Transcode or not makes quite a difference on the hardware needs.