Is 'Anatomy of a fall' free on Amazon prime or have I clicked on it and I will automatically be charged?

[RollingRocking]

I don't think I've ever bought a movie on Amazon prime before? Do you have to put your card details in or do they just charge it to your account?

It's free

If you have prime you are already subscribing. However some programs may incur an additional fee so prime will charge you extra, but you have to confirm your agreement to the purchase.

Thank you.
I thought it was free but I wouldn't put it past Amazon to charge you if you accidentally clicked on something that wasn't free

No, that doesn't happen. When you buy or rent a paid title, it goes to the same checkout page as any other purchase.