A fair market price is whatever a willing buyer and a willing seller are able to agree upon. Historically, it has often been much higher for boids than colubrids. I seem to remember some new ball python morphs going for $50K - $100K - or more. Of course, the market - and the whole economy - have changed for the worse since those days!
With a new morph, there is no way to know ahead of time what a willing buyer will pay for it. BUT - if you overestimate, it is easy to negotiate a lower price. But if you under estimate, you certainly can't RAISE the price later. With a first time morph, the breeder has to depend on his experience and knowledge of the market to make his best guess. The best price will be one that is not so high that all bidders are scared away and won't even negotiate, but not so low that it is immediately snapped up. If that happens, you know you underestimated the market. At least, that is my opinion based on my own experience.