No price drop on the used copies, sadly for those looking to save a few extra dollars with Powerup Pro.
http://www.gamestop.com/browse?nav=16k-3-doom,28zu0,133c-4f-162
edit: Amazon also price matching it on consoles...
Don't know how long they've had it there, but it's marked down from $230. Not a bad deal on a mint Wii U, but you're going to need an external HD if you plan on downloading a lot. Own one of these myself...