Had a little over a week left but just cancelled now since it was on my mind. Could not figure out how to do this without a
Google search. Man, I just hate doing anything related to my Apple ID. Went to tv.apple.com as per that support document and it wouldn't recognize my password. Even copied/pasted it from my password database so I'm sure I was entering it properly. Somehow I got to a different password screen after a few tries and that worked.
Then it wanted me to enter a verification code, which confused me because it was sent directly to the browser instead of texted to my phone as usual. And finally there was the annoying alert that "somebody signed in with my Apple ID". Anyway, it's cancelled now but that was a lot harder than it should have been!