Today!
Cool little vid here to promote it, a lot of it taken from Not Dead Yet, but also some interviews from the last few weeks with Vai, Tosin Abasi, Herman Li, and some kids I've never heard of:
https://www.youtube.com/watch?v=1yQITwSnRh4
So, they went for $80k for the one on the cover of Perpetual Burn and $85k for the one he used to record it (plus $65k for the "learning numbers" one). With any other star guitarist, I'd just be thinking about how ridiculous it would be to spend so much on a guitar just because x, y or z played it, but since these were auctioned literally for a vital cause, it's nice to see they went for so much. And in terms of guitarist worship, his playing at least merits it.