Steak N Shake is currently offering a BOGO FREE coupon for their delicious Steak N Shake milkshakes! From now through December 20, you can use the Steak N Shake coupon to buy one holiday milkshake and get one FREE! They have some super tasty milkshake flavors, including: White Chocolate, Peppermint Chocolate Chip, Cookie Butter, and Egg Nog. Yum. Take advantage of this offer while you can!