DrHotDeal via Buy.com cuts up to 89% off select iPhone 5 cases, with prices starting at $3.99. Plus, all orders qualify for free shipping. That's the first sale we've seen from this merchant, yielding several price lows.
A best bet is the S-Shape TPU Gel Skin Case for iPhone 5 in Black (pictured) for $3.99 with free shipping. That's $3 under our mention from last week for a similar case and the lowest total price we could find for one today by $3.