Yapper_Wireless via eBay offers the refurbished Unlocked Apple iPhone 4S 16GB Worldphone for GSM Networks in Black, model no. MD234LL/A, or White, model no. MD237LL/A, for $239.99 with free shipping. That's $20 below our refurb mention from three weeks ago and the lowest total price we've seen for an unlocked 16GB iPhone 4S. (It's a current low for a refurb by $16.) It's compatible with GSM networks such as AT&T, T-Mobile, and Vodafone; it can't be used with CDMA networks such as Verizon or Sprint.
Note: No warranty information is provided.