Just got one of these for 49.99 at PC world. Ticket on the shelf said 51.97, went to the checkout and it came up at 79.97 so I mentioned the ticket price.
Guy went to check it out but couldn't find it, asked how much it was, I said 50 quid and he put it through at 49.99!
Not too shabby!
In store only - on line price is still 79.97