Amazon offers Prime members the LifeStraw Personal Water Filter, model no. LSPHF017, for $14.29 with free shipping. (Non-members can spend $49 or more to qualify for free shipping; otherwise, shipping costs $5.58.) That's tied with our mention from last July and the lowest total price we could find by $6. This award-winning, BPA-free device enables you to safely drink contaminated water. It purports to remove almost 100% of waterborne bacteria and protozoan parasites and will filter up to 1,000 liters of water.