The rare and beautiful "Guinea" marbles, even individually, can fetch hundreds of dollars each. To find an entire set in mint condition in their original box is, simply put, extremely rare. To then find them for sale is unheard of.
I have only seen these boxes in marble collecting books. In fact this box is the very same one shown in the first three editions of Everett Grist's Big Book of Marbles.
And now it can be yours after you muster the estimated $8,000 - $12,000 it will cost to bid it into your collection.
Source: Morphy Auctions