Redbox has a new promotion. Rent 3 movies with the same credit card and you will get a promo code for a 4th free. Any rentals with promo codes will not count toward the promotion. You just have until 12/31 for this offer- so not much time to rent all those movies.
If you rent 5 movies, you will get 2 free rental codes.
You can get all the details on the Facebook page here.
Does this work with the Groupon code?
Nope. Says no promo codes be used 🙁