Nintendo president Saturo Iwata has said that he estimates that Wii U will cost in the region of 20,000 Yen, which will bring it in at around £150 when it arrives in 2012.However, it is not expected that you'll be able to buy it as a standalone device if a spokesperson at a Nintendo booth at E3 is to be believed.
The unnamed rep told CVG, "Both the controller and the console will be sold as one unit. You won't be able to buy the controller alone."
This would appear to be an insane idea considering the number of people who already own Wiis and would be looking to add the new controller (or platform or console depending on who is talking).
Sources:
BloombergCVG