Ask HN: What do I need to start learning DevOps?

I'd like to learn about devops. I think that hands-on is the best way to learn. I can run Docker and VirtualBox on my desktop, but what about VPS? I guess that there is difference if I'm doing something on localhost and on real server that is on Internet.

I couldn't find any free VPS server providers. Cheapest are about 10 USD per month. What do I need to look for at VPS server that I would like to use for learning?

I know that I'll have to learn AWS, GCP or Azure. I guess that they all have some free tier. Is this correct assumption?

Are there some security practices that I should follow for the very start? I don't want to end up with someone using my test servers for something malicious.

I've read a bunch of horror stories about AWS costs that go through the roof. Can I somehow limit the monthly cap and spending on AWS and other cloud providers?