F-color via Amazon offers its F-color Universal Waterproof Case 4-Pack in Black/Blue/Orange/Pink, model no. 4069847, for $15.99. Coupon code "S2XPC8XY" cuts that to $10.99. Plus, Prime members bag free shipping. (Non-members can spend $49 or more to qualify for free shipping; otherwise, shipping costs $5.99.) That's a buck under our mention of a three-pack from July, $23 off, and the best price we could find. Each case fits smartphones up to 5.7" and is IPX8-certified waterproof up to 65.6 feet.