Hackinscience is a free, open source, and ad-less Python learning platform which runs exclusively on your donations.
You can sponsor me on Github, and choose between multiple tiers, some of them just giving me more time to work on Hackinscience, some other will provide your with one-to-one video chat with me.
If you just want to help, but stay anonymous, you can donate on liberapay/JulienPalard, it's a good way to say "thank you" while providing me with incentive and motivation to keep focused on open source software in general, including hackinscience.