The answer to that will be everyone's favorite "it depends". Specifically, it depends on everything you are trying to do. I have a fairly minimal setup, I host a WordPress site for my personal blog and I host a NextCloud instance for syncing my photos/documents/etc. I also have to admit that my backup situation is not good (I don't have a remote backup). So, my costs are pretty minimal:

• $12/year - Domain
• $10/month - Linode/Akamai containers

The Domain fee is obvious, I pay for my own domain. For the containers, I have 2 containers hosted by the bought up husk of Linode. The first is just a Kali container I use for remote scanning and testing (of my own stuff and for work). So, not a necessary cost, but one I like to have. The other is a Wireguard container connecting back to my home network. This is necessary as my ISP makes use of CG-NAT. The short version of that is, I don't actually have a public IP address on my home network and so have to work around that limitation. I do this by hosting NGinx on the Wireguard container and routing all traffic over a Wireguard VPN back to my home router. The VPN terminates on the outside interface and then traffic on 443/tcp is NAT'd through the firewall to my "server". I have an NGinx container listening on 443 and based on host headers traffic goes to either the WordPress or NextCloud container which do their magic respectively. I also have a number of services, running in containers, on that server. But, none of those are hosted on the internet. Things like PiHole and Octoprint.

I don't track costs for electricity, but that should be minimal for my server. The rest of the network equipment is a wash, as I would be using that anyway for home internet. So overall, I pay $11/month in fixed costs and then any upgrades/changes to my server have a one-time capital cost. For example, I just upgraded the CPU in it as it was struggling under the Enshrouded server I was running for my Wife and I.