There are fedi hosting services that let you host thousands of accounts for like $200 per month. Graf used to (lie and) say it cost him $3000-4500 per month, and he’d collect that much in donos.
Discussion
Are these sites hosting the big mastodon instances? Basically only poast and baest are over 1k active I think over on this side. Probably kf too when it's userbase comes back...