Everyone above has mentioned the many possibilities of price fluctuation.

I think if you are seeing a piebald for $750 and another for $5000 the animal for $5000 is more than a piebald, such as a piebald het or (insert other morph here). They look the same but have much more going on genetically that's more valuable to a customer. I haven't seen a hatchling or even sub-adult piebald for $5000 for quite some time now.