4-Pack Membrane Solutions 0.1 Micron Straw Water Filter $23 at Amazon

amazon.com has a 4-Pack of Membrane Solutions 0.1 Micron Straw Water Filter for $39.99 – $15 when you clip the coupon on the product page – 5% when you checkout via Subscribe & Save =  $22.99. Shipping is free on orders of $35+ or Prime.