[zufallsheld]

Do you know https://en.m.wikipedia.org/wiki/Flattr? They did something similar.

[strnisa]

Flattr was a micro-donation subscription service where users set a monthly budget that was allocated to creators.

Small Transfers is for usage-based billing of online services and APIs. There is no monthly budget, wallet, or pre-funding. Customers are charged only for actual usage.