This really needs to be higher.
Running a Mastodon or Lemmy server is surprisingly cheap. With some specific tweaks and rules (esp. hosting images and video elsewhere), it can get even cheaper.
If your only goal is to break even, then it’s amazingly easy. Roughly 1 of every 20 users contributing $1/month. Adjust the numbers as you see fit.
Or a single, non-datamined ad at the top of the page.
That’s not entirely true- you can upload your own, but you can only seed to users that do have port forwarding. On many trackers, that initial seed is all going to seed boxes with an autograb script enabled anyway, and those do have port forwarding.