I think even small contributions make a lot of sense, especially if you gradually increase them over time. This is not to gain fame, it's to contribute and support sustainable development. My contributions are spread thin and the amounts sometimes look silly ($5 or $10 per month for a developer), but I believe they do make a difference and I intend to slowly increase them all as finances allow.

I'd suggest looking at Clojurists Together, Github Sponsors and direct sponsorships through PayPal subscriptions.

I look at it as an R&D expenditure (and it goes into my financials as such).