im running a bare bones instance, just starting to get some users. i am using one of the higher cost providers in AWS, and my total costs are ~$1.02/day. i could probably get to about 25 users before i have to double these costs in the form of the next tier of hosting, but then i could probably scale to 250-500 users. for ~2$/day. i can imagine donations allowing me to scale to many thousands of users before the leecher/donation ratio tips.

its not that expensive, but then, i dont have a ton of leechers either.