That's relatively steep for a normal male, however, if you are happy with him- thats money well spent.

In order to make a 100% DH for pied and hypo without proving them through breeding (which you said he hasn't), is to cross a visible pied to a visible hypo. If this guy doesn't have either in his collection, then you probably don't have a DH snake. Considering the cost of true double hets and even possible hets, it sounds like he just exploited that fact that you are new to the game and embellished the deal a little bit.