Spigen Inc. via Amazon offers Prime members the Spigen Tough Armor Case for iPhone 5 / 5S in Metal Slate, model no. SGP10490, for $14.49 with free shipping. (Non-members can spend $35 or more to qualify for free shipping; otherwise, it adds 5.37.) That's the lowest total price we could find for any color by $5. It features an air-cushioned, spider web pattern hard case and purports to be slimmer than most other cases on the market.

Also available for Prime members is the Spigen Tough Armor Case for iPhone 5 / 5S in Champagne Gold, model no. SGP10584, for $14.50 with free shipping. (Shipping for non-members adds $5.74.) It's also a price low by $5.