Interesting idea. https://minus.social/
Of course it has flaws. One can just create another account. But it more an art than real software.
Another flaw - cost is linear. I guess service with unlimited number of posts but increasing cost would be more interesting. First post - free, next $0.01, next multiplier * cost of previous cost. With multiplier 1.1 10th post cost barely $0.02, but 50th is almost $1 and 99th is almost $100.
This is a brand new server run by the main developers of the project as a spin-off of mastodon.social It is not focused on any particular niche interest - everyone is welcome as long as you follow our code of conduct!