About $900 per month, which is non-aggressively asked for (a single button on a single website with no pushy messaging - just "buy the server a drink").
The costs are below this, in the region of $600 most months except when TLS certs and domain names roll around. I donate extras throughout the year to causes related to the one website that delivers the donations.
I do receive a few other donations from a few other sites based on "pay what you feel it is worth", and those amount to another couple of hundred dollars.
This just sounds like bad sales. If you aggressively asked for donations, some users will get mildly annoyed, but then the service can still operate - ie not shut down and users can get utility out of it.
The costs are below this, in the region of $600 most months except when TLS certs and domain names roll around. I donate extras throughout the year to causes related to the one website that delivers the donations.
I do receive a few other donations from a few other sites based on "pay what you feel it is worth", and those amount to another couple of hundred dollars.