Apple TV - What is included?

I've watched 1 series on the Apple TV+ subscription and have found that virtually every movie/tv show is chargeable in some way! Even the tv series that are free on the BBC are charged in Apple TV+. My question is, what am I paying for? am I just missing a category or something on the app where the included shows/movies are stored! I'll be honest the UI isn't too helpful.

Seems a lot of money to just be for additional renting/buying movies and series. any help would be appreciated.

Many thanks,

Jonathan