Free Redbox DVD with Discover card This post may contain affiliate links. Please see the full disclosure policy here. Posted on November 11, 2009 Written by Mary Leave a Comment Do you have a Discover Card?? If so, you can get one free rental at Redbox with code: KJXMT3. Just enter the code and use your Discover to check out- you will not be charged unless the movie is returned after 9pm the next day! Thanks, Myfrugaladventures!