Hello dear Arch Linux team! I would like to ask you a series of questions:
1. Is Arch Linux completely free? If I use Arch linux, create various programs on it, do anything in general, both commercial and non-commercial, do I have to pay anyone?
2. What does it mean that Arch Linux has proprietary software? Does this mean I have to pay someone something?
3. How do I know if I'm using a free program or a proprietary one?
4. Do I have to contribute to Arch Linux or is it optional?

P.S. I really liked the idea of Arch Linux. So I would like to get to know her better :)