In the mood for some good mood food? Arby’s has the answer for you. Join Arby’s Extras and get a free Classic Roast Beef Sandwich with purchase of a drink, just for signing up. When you join Arby’s Extras you can get exclusive deals, offers and discounts that are not available to non-members. It’s easy, and quick. Simply fill out the online form and you can get your coupon for a free Arby’s Classic Roast Beef sandwich.