It made its exit from the Play Store device section a few months ago, but there are still some Google Play Edition Sony Xperia Z Ultras floating around out there. Expansys has the device in stock for just $269.99, but it's not exactly new.
The Z Ultra is still a presentable phone, if you're into the whole phablet thing. It has a 6.4-inch 1080p screen, a Snapdragon 800, and a 3000 mAh battery. This is the Google Play Edition, so it has Android 4.4 with no OEM modifications. It isn't clear how much longer it will be getting updates, though. Google seems to be spinning down the GPE program.
This listing on Expansys is for "B stock," meaning either open box or refurbished. The phone should be completely functional, but you get a big break on the price.