Movie tickets are sold at some convenience stores and department stores. This is what movie tickets look like. As you can see, we went to see Ratatouille or remi no oishii restoran in Japanese (Remy's Delicious Restaurant.) The one on the right was Little Brother's (he's 11). Big Sister is 15 and had to pay adult admission.
When you go to the theater, you still have to stand in line to reserve a seat even if you have bought a ticket. You can choose your seats if you get there early. The white ticket stub is taken from you, and you are given another ticket with your seat number on it. You get to keep the part with the scene from the movie.
Years ago there were fewer theaters than there are now. You had to stand in line for hours. They even sold standing room only tickets. Some people had to stand during the whole movie!