Hey some good people are here on Lemmy under selfhosted. I am sure there are more.

A server can be nearly anything, a $50 used computer can work, the cost of hard drives can run a bit more. Its a neat little hobby and doesnt have to be expensive. OpenMediaVault (as the OS) is free and get you started as a NAS out of the box.

In any case, lots of people are happy to help and there are tutorial videos as well.