Blue Pearl is the ultimate freelance establishment, and this includes the front desk personnel! Basically, the price is whatever they think you are willing to pay without leaving. LOL
If Diane is working, she (in my experience) always stuck to the standard price list, which I think was $40/$60/$80 door fee for 30/45/60 minutes.
However, once you get into the room, its like haggling with a street vendor. It all depends on the girl, how busy the shift is, if her rent is due, what you request, and so forth.