I don't have updated prices, but the Mickey, red, 4x6 autograph book last May was 6.95.
I read on an ebay listing that that one has been discontinued (was there in December) and they were starting at 9.99.
But I've just never found the official autograph books to be THAT expensive that I needed to get one ahead of time...in fact sometimes I'm surprised at how relatively inexpensive things are (I know, I'm weird), b/c I have an expectation that they are going to be 5 times more than they turn out to be. Still haven't bought a t-shirt, b/c those are more expensive than I feel they should be, but the toys and autograph books and such just don't seem like that much moola, sometimes, to me.