[r3bl]

Yeah, I agree with the other comment.

> "For us, in order to be able to cover our server costs, we ask our users to contribute a tiny amount if they find the app useful. Donate to see the detox counter again."

As far as this message goes, I'd just remove the word "server". We all know that's not the only cost associated, so pointing it out as the only cost seems... dishonest? Maybe you'd want to link the word "costs" to a web page that elaborates on the costs a bit. Not with concrete numbers, but more like percentages: 60% on the time maintaining it, 10% for the server and domain(s) etc.

As far as the funding model goes, I feel like pay-what-you-want would be a good strategy for this use case, but that's up to you to decide. I'm certainly bad at monetizing my projects, so I'm in no position to make suggestions.