I've had a week to think about this.
I think my response if people ask "can I join your instance Bob?" will be "no, make your own!" 😅
This isn't a greediness thing. I think it's a cool idea for people to take control of their own data and computing. 💻
Besides, giving masto.host €5 a month to keep them running is going to work out better for the wider community than paying me $1 to spend my free time policing an instance.