Was just in ASDA Dundonald (Belfast) and bought Rock Band for £12.75 reduced from £17.00.
Still showing as £41.43 online so its probably dependant on your local store.
Developed by Harmonix, developers of the blockbuster Guitar Hero franchise, Rock Band is an all-new platform for gamers to experience music, giving players the chance to rock in the shoes for the biggest guitarists, bassists, drummers and singers of all time - as a solo superstar or as part of a hard rocking band.
Rock Band delivers the most authentic music game ever - by challenging rockers to master lead guitar, bass guitar, drums and vocals. Built on unprecedented deals with top record labels and music publishers, the music featured in Rock Band spans all genres of rock and includes many master recordings from legendary artists.
Rock Out Your Way!
Unrivaled Song Library!
Rock 'n' Roll Never Dies!
Play Together In Your Living Room Or Across The World!