Many years ago, when movies were shown in theatres, typically they showed two films. In some cases, they didn't even bother chasing people out; you could sit in the theatre all day if you wanted. (In places where it was very hot and homes didn't have air conditioning but the theatre did, sometimes that's what a lot of people did.)
Actually, for your money, starting at a nickel or a dime in the 1930s, by the 1960s it was possibly 50c, and as late as the 1970s to early 1980s you might get into a movie for $2 - you got
- really cheesy ads with soda cups and popcorn buckets dancing with candy bars and stand-up hot dogs, telling you "lets go out in the lobby" and buy some of that wonderful artery-clogging food where nobody ever said popcorn with salt and butter, a hot dog with cheese, nachos with cheese, soda with real sugar, and candy bars the size of a brick were bad for you
- trailers for upcoming films, in many cases the trailer was better than the movie
- a Newsreel (until television became popular),
- a cartoon, typically Donald Duck, Bugs Bunny, something from MGM, or Woody Woodpecker. The cartoon was probably from the studio that made one of the movies that you saw
- the first film
- a short intermission so you could go take a pee and hopefully buy something at the refreshment stand (presumably in that order)
- a serial (again, until television became popular)
- possibly a second cartoon or a The Three Stooges short
- and then a second movie.
Inflation kind of killed this off until now, for $7 to $10 you get one movie, and sometimes even a boatload of advertisements for anything from local lawyers to recommendations to enlist in the National Guard. Plus trailers for other films, and ads for all of the stuff that the theatre tries to sell you, which, thanks to people concerned about your health, you're probably not buying it as it tastes terrible, because all the stuff that tasted so good and is so bad for you has been removed.
The only places left that offer more than one film for your ticket purchase are Drive-in Theatres
and specialty cinemas.