I have a w850 for sale that I used for barely 2 months.. I paid over 400 for this when I got it. Currently, it is on ebay for 370 + shipping. I will sell mine for 300 shipped. It comes with box, memory card (1 gig) and all accessories. For more information on specs or pics please visit:

http://www.gsmarena.com/sony_ericsson_w850-1563.php

Remember, mine is white which is more unique than black. It also comes with a "medallion" thingy that the black one doesn't

 

and yes it is unlocked to be used with any GSM network (cingular, tmobile, etc)

 

sold!