Be careful with EBGames.com honoring prices that later go up. Not only will they charge you the new higher price, but in my experience they won't even e-mail you to tell you they are doing so! I understand not being able to give a mistaken price, and I understand even cancelling the order. Inexcusable to charge higher prices with no warning though, like they did to me fairly recently.
That being said, it wouldn't be too shocking if NG Black actually is in the $20-$30 range, seeing as how it is essentially a greatest hits release of a high selling game with some realtively minor updates. Kinda like VF4 Evo or Silent Hill 2 GH releases for PS2, or Morrowind GOTY for Xbox.