Mullvad is the service that Firefox use, I took that as an endorsement and tested them, it worked well (on Linux, which has a command line controller for a service that is installed) once you've got used to how it's set up. They seem to do anonymising thoroughly. IIRC you can even mail them cash.

Edit: I should say, I used their support email, they responded pretty quickly for a cheap service, offered a beta client and that fixed the issue (I'd actually tried the beta by the time I got the email back, but still).