Today only. ISOPURE SALE + 20% OFF site wide with Vitamin Shoppe coupon code ‘TWENTY16‘ + Free Shipping over $25. The price for 3LB of the popular Nature’s Best IsoPure – Zero Carb Isolate protein drops from $42.99 to $34.43 at checkout. Available in 5 flavors. This is an all time low price we saw by $12.. Pure Naked Protein: Isopure WPI powder contains 26 grams per serving of unadulterated 100% Whey Protein Isolate, stripped of fat, carbs, fillers, sugars and lactose.