Amazon offers 50 Nuk Seal N Go Breast Milk Bags for $7.39. Clip the 30% off coupon on the product page and it drops to $5.17. Plus, Prime members bag free shipping. (Non-members can spend $49 or more to qualify for free shipping; otherwise, shipping costs $6.40.) That's the lowest total price we could find by $2. Each bag features a double zipper seal.