I agree that Amazon Prime has a "tricky way" when viewing various video offerings. You have to look closely to make sure it is not one of their free now but pay after a little usage. The good point of Netflix is there are none of these slight of hands to get your money.
You can bet the farm that Amazon is getting a cut from what HBO, Cinemax, etc are getting from this creative way of fooling the user! I made the mistake once of missing the small print and getting an extra charge on my bill. Never again!!!