The UK price for the Nexus S just became a whole lot (nearly 22 percent) more attractive, thanks to the Carphone Warehouse slashing the SIM-free purchase option to a sweet £429.99 ($668). Contract-saddled pricing has also taken a tumble, as the Nexus S can now be had for free on two-year agreements costing £30 ($47) per month. Good news all around, then, but be aware that the handset is now listed as being on back order, having been "in stock" earlier in the week. Speaking of delays, we're also hearing Best Buy's guaranteed Christmas delivery -- something proudly signposted on the Nexus S online order page -- might very well miss Santa's delivery window. A couple of our readers have received emails from the retailer advising them that their Gingerbread packages will be shipped "within the next 1-2 weeks," but might not get there by December 24th. So happy holidays and best of luck!