Note that the "free trial" generally requires you sign up to the recurring monthly plan so when the 3 or 6 month trial runs out you are automatically on the paid plan. Sure you can cancel it, but I bet a lot of people don't - at least not straight away.

I'm trialling it (poorly) with the 3 months free I got with a Chromecast. I have a calendar reminder to cancel it if I want to.