Ive been considering this aswell. I think it wouldnt take much compute to host your account, or a couple if you invite friends to join. Its a website and a database after all. The bigger chunk of space consumed will be any images etc you share across instances, as they all go back to the home instance (your server) but images dont take much space.

Im still new to this as well, but this is what i think how it works. Let me know how you go!