Right now I'm hosting HomeAssistant on a NUC which takes 15 W. I'm guessing that if I want to serve my website, mastodon, pixelfed, peertube and perhaps other things in the future I'd want something which also runs with a mobile CPU like the NUC, just newer and faster and in a different case so I can build in hard drives, etc. inside of it. But yes, I'll need to calculate the costs for all of that.