Females do cost more. For example a female piebald (in my area) goes for about $650. A male piebald goes for about $500.

Depending on the morph, they can either be cheap or expensive. Right now a normal male is around $40 and female around $60 while something more fancy like a Clown, a male goes for about $700 while a female goes for about $850.

Something less exciting like a pastel should not be higher then $150.

It really depends on where you go, where you live, and what you want.