Well, I think if you called several studios and ask what they would charge.
(don't tell them that you are doing the shoot
they may not tell you anything)
Tell them that you want a base price and that you are shoping around for the best price and that you have heard great things about their work.
I have done this and it works for me.
The price they give you I would charge a bit less based on your experance shooting. If everything works out well (knock on wood
) they will have you back for more and spred your name & number around.
make cards to pass out to people
and when you see how things turn out then you can up your price.
New and refered clients (around here anyway) some times get anywhere for %10-%20 off the first shoot.
Hope this helps.