It depends on, what you are afraid of.
A VPN would never protect you against fishing mails or malicious downloads, but is well suited if you do something on the net, that you would not like to get confronted with later, e g if you watch porn or expresses critic of your government or state. If you torrent copyrighted content, you definitely need a systemwide VPN capable of torrenting.
Torrent is an ideal way to get & share big files. And there are plenty of open source operating systems and other free stuff out there, but the likelyhood that people torrent movies is present. Many VPN prohibit torrenting.
Think about that your browser fingerprint goes right through any VPN. Sites you visit may not know your name but can follow you from session to session on the internet narrowing in who you are every time. You should use a 'fresh' browser every time with no bookmarks, coockies or extentions or any customizations at all.
This thread is about using a torrent client in a browser window and eventually through opera VPN. It would be the only way to torrent through a VPN tunnel for free. I have never managed to make that work. May be it is because the VPN is Canada based, and there it is prohibited to torrent through a VPN.