Activate this link to take 20% off one item at GNC, including on the popular Muscle Milk supplement drink. Popular in gyms across the country, Muscle Milk revs up the body's ability to burn fat and build muscle. A 2.5 lb. container, normally $49.99, is now on sale for $25.99 and drops to $20.79 with the code. GNC carries a large variety of Muscle Milk flavors, including Mocha Latte, Dark Chocolate, Strawberry and Mint Chocolate Chip. Shipping is approximately $5 and sales tax is charged in states with GNC retail locations.