Hackinscience is a free, open source, and ad-less Python learning platform which runs exclusively on your donations.
You can donate on liberapay/JulienPalard, this is the proper way to buy me some coffee or just say "thank you".
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 it's easier for you, I also have a Paypal account: paypal.me/JulienPalard.
Gandi is hosting HackInScience.org freely, which helps a lot, and we really wanna say thank you for that!