You may want to look on Ebay from time to time although that is not a perfect indicator of value. If I had to guess, I'd say $300 for the mint set and $200 each for the used sets, but you have to find a collector who is interested in them.I have an unused set of Raschig 9-balls. They are with their original box and the balls have no numbers. I also have several sets of Raschig 15 ball sets with their original boxes. I'm thinking of selling these sets but have no idea as to their value. Can you help?