I went into Virgin Megastore in the Trafford Centre the other day and they had SSX on Tour for the PS2 for £4.00. I've checked online at Virgin and it's £6.00 for some reason but the next cheapest after that is £11.94 at Gaamesbuyer.co.uk.
I've got this game and it's very good. Excellent gameplay, graphics and a wicked soundtrack.
EDIT - This now seems to actually be £4.00 online as well with free delivery according to The_Killers