Re: Speaking of...
I've had a free Prime membership a handful of times, always initiated when the morass of 'are you really sure you don't want to not continue without not having Prime' links while just trying to order something led down the wrong path, in spite of my best efforts to avoid it.
In every case I have cancelled - or started to cancel - membership within minutes.
In every case I have had to resort to the internet to find the mechanism to cancel the membership - most recently, the links required to cancel did not appear on my account until over twenty-four hours later.
You'd think they'd notice...