Arby’s: Buy One Get One FREE Reuben Sandwich This post may contain affiliate links. Please see the full disclosure policy here. Posted on March 12, 2012 Written by Mary Leave a Comment Head over to the Arby’s Facebook Page where you can snag a buy 1 get 1 FREE Reuben Sandwich coupon valid 3/16-3/18! I have tried these and they are very good. Reuben’s are my all-time favorite sandwich!!