Yes, the price you pay is expensive. The House takes half of the courtesans earnings and the Nevada Brothels have a monopoly on clean, safe, legal sex in the USA. The ladies are trying to make a living, the need to charge a high price is understandable. Each lady is a sole source provider. They are all different individuals and have different prices for their service. Buying or selling intimacy is not easy to do. The emotional toll on both the buyer and seller is very high. It is no wonder many of the ladies have short careers as sex workers.
I would say a successful negotiation is when you feel you did not pay more than you could afford to pay and you do not feel you insulted or took advantage of the lady with your offer. Do not haggle. If you can not reach a price agreement by exchanging two offers, then express your regret and leave. The lady may be using the negotiation as a way of saying she does not want to party with you. Isn’t it kinder to let the gentleman believe he can’t afford the price, rather than telling him he is too undesirable.