You need to be endorsed to submit on the arxiv, but this is very easy to get as long as you work with someone from the field.
I'm very politically opposed to having any scientific paper hidden behind a paywall (that can often get extremely high for people who just wants to catch up on some science), and I truly believe that it should all be available for free. I guess the journals themselves need to make some money, but charging $50+ for a single article is a bit outdated in my opinion.
I fully agree with this! I am now even refusing to write referee reports for non-open-access journals. That is of course very little, but we need to start somewhere, don't we?