I bought a spiral bound book of different colored index cards for well under $2 at
WalMart and the characters signed the unlined side of the card. The colored cards were fun for DD5 because she got to choose the "perfect" color for each character while we were waiting in line. Sounds silly, but she REALLY got into picking card color. I then bought a 4x6 photo album and put the picture on one page and the autograph on the facing page. I totally intended to scrapbook the character photos/autographs, but the album turned out so well that I left it "as is." My kids ages 5 and 3 absolutely love to look at the album over and over and I don't have to worry about them wrecking a scrapbook I worked on for hours.