Seems a fairly popular and handy industry term. I don't know the industry, so at first glance, it looks comparable to "fashionmistress.com" (as a culture term), but considering that there are many hits for "Fashion Master" spanning businesses, conventions, educational programs, etc... it seems pretty good.
I think I would have to be more aquainted with the fashion industry to even hazard a guess. It feels like it would be most useful to a business who uses it in its name. At that, I'd say maybe $500-$800 tops. This is the most I would recommend a design client to pay for it (they would have to decide if it was worth more).
~ EG