By Sara Morrison LOS ANGELES (TheWrap.com) - 'NSYNC may have joined Justin Timberlake for fewer than two minutes of his big VMA retrospective medley, but it was enough to give the band a big sales bump on iTunes' and Amazon's sales charts. Among the increases logged at the two music stores, Timberlake's "Justified" jumped 1,876 percent and his former boy band's "Bye Bye Bye" jumped 156 percent on Amazon's "Movers & Shakers" chart, while their greatest hits album, released in 2005, hit No. 10 at Amazon and No. 18 on iTunes. Their 2000 album "No Strings Attached" hit No. 11 at Amazon. ...