This Sawyer Products Mini Water Filtration System drops from $19.97 to $13.95 at Amazon. Shipping is free on orders over $25 or with Amazon Prime (get a free 30-day trial). The best price we could find anywhere else is $20. It can remove 99.99% of all bacteria and includes a 16-ounce reusable pouch which makes it easy to filter water and squeeze it into a water bottle or hydration pack. It can filter up to 100,000 gallons of water. Shipping adds $10.17 for orders under $25, and sales tax is charged in most states.