Ace Teah via Amazon offers the Ace Teah TPU Waterproof Phone Case 2-Pack in Black and White for $9.99. Coupon code "S5O6IZ96" cuts it to $6.99. Plus, Prime members bag free shipping on all orders. (Non-members can spend $35 or more to qualify for free shipping; otherwise, shipping costs $6.22.) That's the lowest total price we could find by $8. It features a close-knit swivel/curved snap lock and is compatible with most smartphones up to 6".