$150 more than the Google Play Store price for the same exact handset.
The Google Nexus 4 is a good example of supply and demand. With supply limited, T-Mobile and Daily Steals get to demand $150 more for the phone than Google is asking. Of course, if you don't mind getting locked up for two-years, you could pay the subsidized $199 price (after a $50 mail-in rebate) at T-Mobile once inventory returns.
You might be getting tired of waiting for the Google Play Store to once again show the red-hot handset as being in stock. Until then, if you want the model badly enough, you will need to pay up for it. Heck, the $499 beats the $649 price that the phone was going for on eBay.
source: DailySteals via AndroidCentral