I use Mullvad. It's 5 bucks a month and regarded to be the best in tech circles (search hackernews). They take privacy very seriously. You can even send them cash anonymously to use! I've been with them for almost 5 years and can't recommend enough.
I'd really advice against free VPNs. They have to make money somehow. It will either come from your selling your data and/or using your system resources. My $0.02.