Ask HN: If your project is free, what are you building and why keep it free?

I'm curious about projects that are launched and run for free.

What are you building? How much does it cost you to operate? How long do you plan to keep it free?

Do you have a monetization plan later, or is the goal something else (learning, community, portfolio, etc.)?

Would love to hear about your projects and how you think about sustainability.