The bad economy is good news for movie theaters. In tough times, people are more willing to shell out money at the movies to escape into a fantasy world for a few hours.

But a night at the movies could be costing you more than you bargained for. Here are a few things you need to know before your next night at the Cineplex:

The theater gets paid twice every time you buy a ticket. How? Well, in addition to selling you a night out, they’re also selling your eyeballs to advertisers. Right now theater owners make more from the pre-movie ads than they do on actual ticket sales. So don’t expect to see ads go away anytime soon. Studies have shown that most movie-goers don’t actually mind them.

Next, the theater makes more money if you DON’T come on opening night. That’s because theater owners pay a percentage of ticket sales to the studios and that percentage goes down the longer the movie plays.

Something else you need to know about a night at the movies: Concessions are highway robbery! Ever wonder how theaters can charge 4 bucks for some candy you can get for a dollar at the drug store? It’s all about psychology!

Richard McKenzie is the author of “Why Popcorn Costs So Much At The Movies.” He says buying from the concession stand is now an essential part of the movie going experience. And because we feel like a night at the movies just won’t be the same without popcorn, we’ll pay any price to get it.