Last night, me and my boyfriend decided that we wanted to go see Superman at the B&B theater. When we arrived, we noticed that there were so many cars in the parking lot and there was a long line at the door to purchase movie tickets. After driving around for 5 minutes, we finally found a parking spot right. When we got to the line, we waited another 10 minutes to get our tickets. Since the Superman movie was in 3D we had to pay extra for our movie tickets. As we were walking to hand in our tickets to the ticket taker, he handed us our 3D glasses to use during the show. Before we walked into our theater, we ordered popcorn, a box of candy, and a large Pepsi. We had to sit in the front row since it was so crowded. After the movie was over, we threw away our 3D glasses into the recycle bin and headed home. 
Question: When did they buy tickets?
when they arrived