@aral Yes, running single-user instances of Mastodon is resource-intensive.
I don't think hosting costs scale with followers though. My single-person instance with 1500 accounts has tripled its followers in a week and it's comfortably within the resources available to it with 25 €/month of expenses. Load has barely changed.
https://respublicae.eu/@praetor/109295906060181251
Moderation and other #MastoAdmin costs however scale with the number of eyeballs, I suppose.