These great salesmen sample books surface once or twice a year and are a wealth of information as to what was still being peddled in a specific year. They typically will fetch about what this one did. I received many questions about this listing, with the main question being, "What do you think it will go for?" My answer was around $500. Everyone thought that figure was much too low given the rarity of many of the diecuts contained within the book. However, when you look closely, many of the diecuts were truncated in some way or were otherwise damaged by being placed in such a book. All were affixed to pages, meaning that if you were successful in extricating them, some paper restoration, and the costs associated with such work, would have to be borne to bring the diecut up to a reasonable collecting standard. As a curiosity, these books are pretty awesome, but as a source of actual diecuts to be displayed outside of its pages, not so much.
One additional note, many of these diecuts were originally produced before 1931. Their inclusion in the book only indicates that Dennison was still actively selling the design in the 1931 Halloween season, not that the design was originally produced in that year.
All in all, I think whomever the buyer was got a fun item at an eminently reasonable cost. Congrats!!