I too have noticed how much more the corns go for in the pet stores. We have a large chain-like (dont know if it actually is part of a chain) pet store that is relatively reliable in their reptile department (their fish are another story). Their normals and amels start at $65 and they currently have what looks to be a creamsicle priced at $99. Keep in mind that these are small hatchlings.
As for the worth of your snake, I paid $35 for my male snow motley at a herp show. I think I got a good deal on him to begin with, but he does have quite a bit of yellow on his sides which isnt necessarily always a wanted trait. Also his motley pattern is much more consistent than on yours.
Of course, just because she doesnt have a high market value, doesnt mean she isnt valuable to you