Idealpoint via Amazon offers Prime members the New Trent Trentium Rugged Case for iPhone 5 and 5s, model no. NT630CR, for $15.95. Coupon code "1630CASE" cuts it to $7.95. With free shipping, that's the lowest total price we could find by $9. (Non-members can spend $35 or more to qualify for free shipping; otherwise, shipping costs $6.16.) It includes three interchangeable back covers.