it is what the market will bare..

Big difference in exchange rates comparing USD to GBP to EUR.
500 Euro is about 650 USD
500 GBP is about 800 USD

On top of that, higher legal risk in the USA has to accounted for in the price.

The question about the fees that Pornstars charge comes up every couple of months.  You should probably do a search on this board for other threads on the subject for more information.

There are three main reasons why:

1.  As someone else said, it's what the market will bear.   There are more people in the U.S. that can afford the higher prices so they charge higher prices because they know there are people who will pay it. That seems a rather simplistic view though.  

2.  You are paying for the "celebrity" factor.  More so in the US than in other countries, we "worship" celebrities.  How many news/gossip programs about celebrities are there on tv right now?  How many programs featuring celebrities dancing, singing, or doing other things?  How many celebrities or pseudo-celebrities have their own shows?  Think about it for a second.  People in the U.S. worship celebrities.  We also pay more money for clothing that has a celebrity name on it.  Buy a pair of Levi jeans and you pay about $30.  Pay for a pair of Calvin Kleins or a pair of jeans with a celebrity imprint on it and you can expect to pay $100 or more - I've seen "celebrity"-branded jeans for as much as $500!  So, the fact that you are scheduling an appointment with a "name" means you are going to pay more because she is a "name".  If you don't think that "celebrities" charge a lot of money, try running a convention list Comic-Con and paying for the celebrities to be there to sign autographs.  The celebrities charge a LOT of money to show up... and then you have to pay a LOT of money to attend, and a LOT of money for an autograph.  Don't you think porn star "celebrities" don't want a piece of that action?  Guess again.  Attend an Exxxotica convention and see how many of them charge for autographs and how much they charge...  We pay for the "celebrity" factor in the non-escort arena so why wouldn't they expect us to pay for the "celebrity" factor when seeing them privately?

2.  IT IS ILLEGAL HERE.  Think about that for a second.  Things that are illegal, things that you have to get on the "black market" *always* cost more.  There are risks involved, you can't advertise openly, and there are other problems.  When something is illegal people will pay more to get it.  

Add to all of those reasons the various secondary reasons like how much it costs these stars to LOOK like stars when you see them - hair, make-up, nails, clothes, etc., the cost of hotel rooms, the cost of plane fares, and all those other expenses that come up when they tour, and you can understand why the costs are so high

I think mrfrench and numpty88 have already covered the key points.

I also think prices are held down by the huge supply of alternatives from Eastern Europe.  

Many European porn stars come from Eastern Europe, so £500 an hour probably sounds like a great deal from the provider's point of view.  That was the sense that I got from the Czech porn star (Jane Darling) and a Slovak porn star (Angel Dark) I've seen while in London.

Getting to low cost supply is also pretty convenient.  A flight from London to Prague takes only 2 hours and you can easily get a round trip ticket for £100.  I've met lots guys in New York that go to Prague to binge on the providers available at ridiculously low rates by US standards.  So I have to assume the same thing happens in London.

how much am I paying to a booker VS the Model ?

@ mrfrench
With all due respect.  I don't worship any one. I've seen plenty of Hollywood stars in public and don't bat any eye at them. I am not a sheep in the masses being led by media.
Prostitution is also Illegal in the UK. Where as " Modeling" is not. A little loophole in the law.

I guess I'd agree with " the close proximity of Eastern Europe as a factor " I 'd gladly pay 800-1000 USD for a date with fave. stars. I could extend the time at UK rates.

But my actual curiosity is how much am I paying to a booker VS the Model ??  
I know girls that are on Pam Peaks site, that have given me prices of 1/2 of Pams $1500 minimum for A listers.  I think the girl deserves the Bilk of funds but the booker puts meeting out of reach.
I have had actual sessions with xxx stars and even hung out with some as a friend. The incite I've been told that some girls make 700-1200 a movie.  So for me a booker ups the price over the top.  
 
Also why doesn't PP update that old information All Over Her Site  lol

1.) coz US market is different than UK market...bigger and the mostly BLACK MARKET