Its a walk up place. ive never been there when it has been busy enough you need to book.
I am personally very much against haggling or trying to drive people down on price. It costs what it costs and you need to value the service they give you. There are cheaper options if you look for them, but you get what you pay for. Besides, ive always found it sours the atmosphere in the room and turns it in to a financial transaction instead of a mutually beneficial time.
As far as i know, hj = £20, b2b = £40 and sex is £60. However sex is rarely an option unless you are good looking or a regular.