Purchased a new device and was offered 30-day free trial for AMC+ and STARZ, neither of which I currently subscribe to, but when I tried to sign up with STARZ it put me in an endless loop of wanting my payment info. I didn't attempt to sign up with AMC+ because, well, you know, fool me once and all that. I guess I'll just read a book.
I think that's typical for these "free" offers. They want your payment info because they'll start charging you automatically if you forget to cancel before the free trial ends.