Rare find of an even rarer Tom Swift Jr. Cosmotron Express

It is not very often you find the last book of a series, especially in the picture-cover era of series books. In this case, a few years ago I found the next-to-last volume of Tom Swift Jr., And His Cosmotron Express, #32 of the 33-book series. Since it is near the end of the series, and thus fewer printings were done, it is very difficult to find the book. For years, a book of this type would command high prices on eBay and other internet sites. I found this book in an Oklahoma City antique store that I bet only had 20 books altogether. I bought it for $1 and to make it even more valuable, I found inside a card from the publisher, Grosset & Dunlap, asking the person who received the book to send two copies of the review to them. I was told these reviewer copies were sent out as "press notice" books, with the idea of perhaps generating some publicity.