Sony Z5 Premium now Available in the U.S for $780
http://festwiz.blogspot.com/2015/11/sony-z5-premium-now-available-in-us-for.html
Despite not being officially sold by Sony , the Sony Xperia Z5 Premium smartphone, which sports an eye-popping 5.5-inch 4K display, is now available for purchase in the US. That's over a week after itwent on sale in Europe. Third party retailers including Amazon and Expansys have both standard as well as dual-SIM variants listed on their website.

As for the price, Amazon is selling the standard model for as low as $778, the dual-SIM variant is available starting at $783. On the other hand, Expansys is selling these models for $780 and $790, respectively.
These are all international variants of the Z5 Premium, meaning they don't come with US warranty. Also they're compatible only with GSM carriers such as T-Mobile and AT&T. There is no word on when Sony will officially start selling the handset in the US.
Source

As for the price, Amazon is selling the standard model for as low as $778, the dual-SIM variant is available starting at $783. On the other hand, Expansys is selling these models for $780 and $790, respectively.
These are all international variants of the Z5 Premium, meaning they don't come with US warranty. Also they're compatible only with GSM carriers such as T-Mobile and AT&T. There is no word on when Sony will officially start selling the handset in the US.
Source