Personally, I wouldn't trust any free (or 10€ lifetime subscription) VPNs. While your ISP cannot see which websites you access, now your VPN provider can. Somehow these providers must stay afloat to keep the infrastructure up and running, so they probably do nasty things with the data they can collect.
Considering
Opera Software's owners are in reach of a regime that kicks human rights and free speech with their feet, I'd be very cautious.
Right now, I'm using Tor on Tails, an amnesic Linux Distro that ships with Tor Browser. I'm in the process of writing recommendations on privacy, but it will take a little longer. I can ping you if I'm done