Expansys USA has them at $580 and $375. What shop do you normally use?
There are several versions, including different colors, but it ranges from $470-580. But even if you go with the 6603 (that's the one Sony sells on their site as unlocked), which I can get from Sony for $535 with a corporate discount.
Also, most people get them through carriers. It's still a pain to get unlocked phones in this country. Up until this point, I've just gotten Nexus phones.