For a limited time, Redbox is offering up a FREE DVD Rental with any DVD Rental when you enter the coupon code FERH493WH4 at checkout!
This discount code is valid online at Redbox.com, within the Redbox app (Google Play or iTunes) or possibly at the kiosk.
Please note that this code does not work on Blu-ray movies.
(Thanks, Freebie Radar!)