Subway is currently running a Buy One, Get One Free promotion on Subway Footlongs. Simply purchase one and receive one sub of equal or lesser value for free. Valid only in app or online orders when you use the promo code FREEFOOTLONG at checkout – the most you’ll save is $7.99. Most Subways should accept it. This coupon may not be valid at all locations and may not be valid on melts, only standard subs.