I don't think it's high if they are quality birds.Day? couple day olds? that is quite high. I have sold older birds for 15$ but they were several months old, usually with scovies the older the more pricey. YOunger ones? well, i have bought those for like 7$ and then even less.. it definitely varies i realize.
As for sexing? very unusual, there are sex linked chocolates.. but otherwise most cannot tell till a few weeks old, the more you see the more you get the look however.
If it's just plain old pet quality, that is quite high.