Last week's nintendo direct just saved me $50

[foxtail]

LemonSlice said:

Oh and do get a USB 3.0 stick. Don't know if WiiU supports only 2.0 but they're faster regardless.

If the USB stick states that it's backwards compatible with USB 2.0 then it should theoretically work with the Wii U, but it will only be as fast as USB 2.0 speeds.