MobilePros1 via eBay offers the refurbished Unlocked Apple iPhone 5s 16GB Smartphone for GSM Networks in Space Grey for $279.99 with free shipping. That's $29 under our mention of a refurb from two days ago and the lowest total price we've seen for any iPhone 5s. (It's also $231 under the best price we could find for a new unit.)

Note: No warranty information is provided.