Yep, imagine that $12k

actually server was/is monitoring 2,160 users, users that signed up for this.
So, just profiteering then.
I used to run a website a few years back, over a million unique visitors per month pushing just over 30GBytes. The server rental was around $8 per month with that data capacity.
So the whole thing cost $96 per year for the server and about $25 for domain name renewal each year.
Not anywhere near $12k a year.
What a shame Viktor, you had something good here and now you've spoiled it.
I believe you, but that was shared hosting and nowhere near what is needed to run this.
P.S. the whole thing dedicated from OVH costs me about $700 / year not to mention work and maintenance, just so you know.
And now i ask you, are you willing to pay $1/month for my work ?
Perhaps you could entertain the idea of temporary and occasional donation banners. Who knows, it could work. And it might also cure the heartburn sensations some of us are experiencing.