Rare coupon alert! FREE Dr. Pepper 2-Liter when you buy a Dr. Pepper 2-Liter and M&M’s! This coupon is up to a $1.48 value. Since this coupon is a manufacturer’s coupon, it can be used anywhere, not just at Walmart. Target shoppers can use this 10% off M&M’s Cartwheel offer and this $1/2 Mars Chocolate Target coupon.