I was going to pounce on this quickly before the seller realized what he had, but I decided to let the rest of the folks here have a turn for a change. 1915-S GOLD $50 NGC MS 64 Sweet piece, but I don't think there's a spot for it in the Dansco...
At first I thought that was just some ridiculous ebay price that you see once in a while. Then I checked Heritage, and it's probably not too far off. What an amazing coin... http://coins.ha.com/c/item.zx?saleNo=1153&lotNo=4309