I'm a scrapper, so I have tons of cute, fun papers, alphabet stickers, and ribbons on hand. We made our own autograph books last time and will do it again this trip -- so quick and easy, and since I already have everything on hand, it's cheaper than buying them.
To do something really basic, cut sheets 12x12 cardstock down to four 6x6 pieces and then take them to Staples, Office Depot, or somewhere like than and have them bound together using either wire binding or comb binding. (Or use 8.5x11 and cut it down to two 4.5x5.5 pieces, or whatever size you want the pages to be.) Then decorate the pages however you want...Disney stickers, cute patterned paper, rub-ons...the possibilities are endless. My girls used their autograph books as combined autograph books and trip journals -- so on Day 1, we went to Character Connection and they got autographs. At the end of the day, they journaled on the next blank page. The next set of autographs then started on the next blank page, and then journaling, etc. They turned out really cute and were quick and easy to do.
The only thing I want to do differently is to make sure that this year, the girls get autographs only on one side of the page (if the book is open, only on either the left or the right side of the page), so that way after our trip we can put the corresponding picture on the opposite page (so if Mickey signed on the left page, then the picture of the child with Mickey will get put in on the opposite page, and so on). We'll see how that goes -- it will depend on if the girls remember to flip pages between characters! LOL This also means there will be more pages in the autograph books this time, but bindings come in several different sizes so that shouldn't be a problem.