Cytosport, the makers of MuscleMilk, 100% Whey Protein Powder 6LBS in vanilla or chocolate. In-store price is $31.99, or add $2.99 for s/h. That works out to $5.33/lb.
77 servings per bag, 130 calories, 3g carbs, 1.5g fat and 27 grams of protein per serving.
$8 manufacturer's discount is valid 8/4/16 through 8/28/16. While supplies last.