Melanie! Come on down. Okay, don't come down but do send me your address.
Melanie guessed that there were 92 buttons and, as you can see, there were 90! So she's the closest. Congratulations! The book is yours...and maybe a little something else, too.
The official count actually surprised me because I could have sworn I counted 93 the first time. (You'll have to take my word that there is only one button apiece in the little bags...) But 90, it is.