Pilot: FREE 20oz Mountain Dew CouponMarch 22, 2011 This post may contain a link to an affiliate. See my disclosure policy for more information. Wow! I’ve never seen a coupon as great as this one. Pilot Travel Centers are offering a FREE 20 oz bottle of flavored or diet Mountain Dew, no purchase necessary!Expires 4/18/11. Excludes regular green Mountain Dew.Thanks, SwagGrabber!