1963 Monster Flip Movies “singles” aren't going to run you too much, but the two unopened boxes I've shared on the archive sold for $6222 in September 2017 and $4740 in May 2013. With unopened "inflation," it's hard to guestimate what one would sell for today!

Check 'em out on the archive: https://www.postwarcards.com/1963-monster-flip-movies-unopened-products/