Either due to its popularity or due to manufacturing delays (probably a combination of both) pre-orders for the Wii U sold out in a manner of days and are now nearly impossible to find. Nearly, but not impossible.
Anyone still needing to find a Wii U for the holidays can find one, but it will cost them. Intrepid entrepreneurs are now trying to hock their pre-orders via eBay and are charging ridiculous amounts to do so. Sellers are charging as much as $1,000 for the black 32 GB deluxe version of the Wii U. The original price for the deluxe version of the Wii U, which comes with a larger hard drive, the NintendoLand videogame, and a charging cradle for the GamePad, is $350.
Of course, no one seems to be jumping at the systems being sold for $1,000. The current highest price for a Wii U pre-order that is actively being bid on at this time seems to be $500, as seen above. Ars Technica points out that a Wii U pre-order did sell back on September 27th for $749, the highest so far.
These amounts could easily creep higher, though, as Christmas approaches and parents begin to get desperate to please their young gamers. So, perhaps those sellers price gouging for $1,000 actually know what they are doing, and believe that if they hold their ground until the Wii U's November 18th release date they will find themselves with an extra $1K for their foresight.