Kingcool via Amazon offers its Kingcool Universal Waterproof Smartphone Pouch in Black for $7.99. Coupon code "NKTPNDZG" cuts the price to $3.99. Plus, Prime members qualify for free shipping. (Non-members can spend $35 to qualify for free shipping; otherwise, shipping costs $6.18.) That's tied with last month's mention and $2 under the lowest total price we could find for a similar item today. It fits most smartphones up to 6.6" and is waterproof up to 30 feet.