Groupon offers the OtterBox Armor Series Case for iPhone 5 for $14.99. Coupon code "SAVE10" cuts it to $4.99. With $3.99 for shipping, that's $4 under a similar mention in October and the lowest total price we could find by $13.
BuyDig offers the OtterBox Commuter Series Case for iPhone 5c in Hornet for $8.50 with free shipping. That's $2 under our July mention and the lowest total price we've seen. (It's a current low for the case by $6.) This case features two layers of protection and an adhesive screen protector.
Need it by Christmas? Upgrade for 2-day shipping at checkout for $11.16 and order by December 22 at 6 pm ET.