Breed via eBay offers the open-box Unlocked Apple iPhone 5S 64GB Smartphone for GSM Networks in Space Gray or Silver/White for $679.99 with free shipping. That's $50 under our open-box mention from last month and the lowest total price we've seen for this phone. (It's also a current price low by $114.)
Note: This is a new and unused item. The box was only opened to unlock the phone.