Re: are you subscribed automatically?
> Having inadvertently clicked a "subscribe to Prime" button
Yes, I've done this myself with the free Prime trial button- something I had no interest in and have avoided in the past. Admittedly, this was my fault for not paying attention as much as I should have been. (It was late at night and I was about to go to bed).
But the fact I should have *had* to pay attention (or rather, shouldn't) shows how borderline dubious Amazon are becoming. It's not just that they would obviously have known this would happen, it's that it was quite blatantly designed that way to mislead and coerce users into signing up for their grab-bag-o'-bullshit Prime service.
There's no other excuse for a page with a single, prominent "button" and much less prominent, lighter non-button-like text for the "continue without signing up to Prime" link. (And FWIW the design of these pages seems to have grown increasingly prominent and "dark pattern"-ish recently).
I cancelled it immediately, but Amazon kindly (*cough*) indicated it would run until the free trial period was over anyway. Aside- ironically- from cheaper postage that I'd rather have paid standard rates for (but had no option to do so because I was signed up for Prime), I didn't use any Prime facilities before the trial expired.
Someone recently put their finger on it when they said "Amazon is not the same company they were 10 years ago. You can feel the skeeviness is creeping in."