UPDATE 7/23: Image was taken off a secondary placeholder file. No change in price has been reported.
Original story 7/22: When the Xbox One was revealed and given a $500 price tag, many were put-off by what they felt was a extreme price tag. With the PS4 being released for a full $100 less, those who are more financially strapped may decide to go with Sony, instead of taking a chance with Microsoft's X1.
However, that price may have changed. While not official, this picture is reported to have come from a Gamestop's retail computer. In it, you can see that both the PS4 and Xbox One have console prices of $399.
Now, this may simply be a placeholder pricing that never got changed, or Gamestop may have put in the wrong pricing into their system, but it is very possible that Microsoft has altered their console price and are waiting to reveal the change.
*This story will be updated as more information comes to light*
Edit: Points against legitimacy of computer image include controller pricing (confirmed to be $59), Territory ID #9999, Excel spreadsheet can be easily faked, and price decrease is very dramatic.