Proozy offers the LifeStraw Personal Water Filter for $19.99. Coupon code "DN1399" knocks that to $13.99. With free shipping, that's the lowest price we could find by a buck, although we saw it for $1 less last week. This award-winning, BPA-free device enables you to safely drink contaminated water. It purportedly removes almost 100% of waterborne bacteria and protozoan parasites and will filter up to 1,000 liters of water. Deal ends May 31.