That sort of thing is impossible to value in this context. You really would need to get it professionally examined, and if you have a good provenance (proof that the autographs are genuine) then that would work in your favour.
My 'autograph' book (actually more of a friendship book) is larger than most, about quarto size, and I always try to attach a programme or some such to the page in order to give it a context.
Chaotica, the daft thing is I can prove all the autographs I've got but I wouldn't part with them for the world, no matter how much they were worth.