Redbox has a promotion running this month as well. If you rent a DVD from them, you can come over here and enter the code from your movie. They will give you another code for a free rental. This is available once per account through 9/30.
If you do not already have a Redbox account, you might register here and get a free rental with your first online reservation of a movie. Then try the promotion above later this month to get a second rental free.
Thank You MyFrugalAdventures!