California said:
...in LA it runs about $400/$500 per hr for a nice piece of ass.
Not if you know where to look.
You could spend even $$150--$200 for some decent action.
On the other hand, you may lose a fortune on outcalls and get no action. LA and Vegas are infested with scam artists running outcall agencies that claim to offer escort service, and yet when the girl shows up, she takes your $300 and just dances and asks you to play with yourself. Anything more is worth much more dough. Typically, such an encounter lasts 10 to 15 munties, and your out of a lot of cash.
In LA anyway, I think that outcall is a bad idea, unless you know the person or agency you deal with really well. There are many legit ones out there, but the price, the privacy concern, coupled with other factors make it not so tempting. If anything, go for incall when in the US. At least they won't know where you live and can't attempt to scare you by reporting you to the cops when you try to call them on their scam. Also, you could walk away more easily if you don't find the girl to fit the description. Heck, even some montreal agencies come to LA area and offer incalls.