Amazon has the Mad Catz Rock Band 3 Wireless Fender Mustang PRO-Guitar Controller (Nintendo Wii) for $53
with free shipping. Also available for Playstation 3 for $54
and for Xbox 360 for $56
with free shipping. Features 17-fret touch-sensitive neck with six buttons per fret provides a total of 102 active finger positions and six low-latency strings for actual note strumming.