I usually pay about $400. Conversion rate is about 80%. Like someone else said, I don't usually ask unless I think it's a "yes" already. I have blown $500 on a couple of occasions for OTC which was a total waste of time and money. No passion, mechanical, no DFK. Have also had some amazing encounters which were unforgettable. Still prefer a $200 ITC which features everything except a bed and a view.
@samiel
"I almost pulled the trigger on an absolute fantasy girl who wanted $1500/hr"
A $200 meal is not 10x better than a $20 meal. The best $1500 slut in the world isn't 10x better than a good $150 one who knows what she's doing, in fact the expensive one is usually worse. She will be good at faking, because dudes who drop $1500 for an hour of pussy need to be fooled into thinking that they're amazing men who can please a "model" type girl. She probably also has more strict boundaries though not always.
But those who know what real passion is will appreciate the more subtle and sincere ways of the girl who likes/needs the money but who fucks for the excitement. Assuming you're well groomed, she finds you attractive, and that you are compatible. The money is on the table, but she wants to have at least one orgasm and would be very disappointed if you didn't cum. She knows how to fuck and she wants you to praise her for how she handles your dick. She loves taking good dick, not just your money.
The more you are willing to pay them, the less they will respect you, and the less they will want to, so, even if you can pull it off, she's not likely to be motivated. You tell a girl you will give her $1500 to do something with you that she will do with someone else for free, and the respect is gone. Women are more turned on by a man who says a firm but calm "no" than one who does everything she asks him to do.