I have to disagree just a little on eBay being unreliable... Yes there are many misrepresented marbles listed, but given the fact you are halfway capable of id'ing marbles, if you look at multiple true examples of COMPLETED dragons, cub scouts, Spiderman, zebra etc, you are gonna wind up with a pretty good ballpark of what yours will sell for. Just use some discretion and common sense and always watch the reputable sellers like many you have listed... Cedarman7 is great. eBay is a great platform and in a lot of ways is a cornerstone for the marble market value so to speak. There's just not many other places to buy and sell. Just do your research and be confident in your bid before you go bidding over 20 on something and you'll almost never lose your arse in my opinion