Rain: The illustrator of that particular book (Charles Harper) is more collectible than the Giant Golden Books themselves. (Books are collectible for many, many reasons. Finding what makes an individual book special helps you price it well.)
You might want to try a search on Abe with no title, Provensen as the author, Simon & Schuster as the publisher, the date set between 1940 - 1960, and the first edition button checked. This will give you a feel for the price range of your book.
You have a GREAT book there. Not only will you eventually get a nice sum for it, but it will really help you learn how to research desirability. Everything this book has taught you already will be used nearly every day of your life as a book seller.