If you like going to movies, you'll love going for free. Read on ...
Lots of studios run free screenings of movies a week or two before they come out. I suspect it is to help build "buzz" for a new movie. I find that the movies are usually shown mid-week and usually only at one or two theaters in a given city (maybe more in big cities).
TIP: If you get an email offer about a screening, you should sign up RIGHT AWAY, as they usually fill up fast. You typically are NOT committed to going. But the flip side is that seats are NOT guaranteed either, so you want to get to the screenings a bit earlier than normal to get in line for a decent seat.
Here are two websites you might want to sign-up via to get notified of upcoming screenings:
If you know of others, please let me know.
Also, you might want to search for feeds on Twitter that highlight screenings in your area. For example, in Portland, a good Twitter feed to follow is: @ORScreenings
Finally, HERE is an old post from me regarding getting concessions at a great price every time you go to Century, Cinemark, or Rave movie theaters.