Groupon offers the MuscleTech Premium Whey Protein Plus 5-lb. Bag
in Chocolate, Cookies/Cream, or Vanilla for $39.99. Coupon code "VISA5" drops it to $37.99
. With free shipping
, that's the lowest total price we could find by $9, although we saw it for $10 less in July. It features 20 grams of protein in each serving.