It cost USD 1K to 2K per hour, but it's not worth it as you can find younger and prettier girls at the USD 400+ price range with better service.
http://www.theluxurycompanion.com/page.php
Book once when a porn star toured NYC. Business was slow and got a discounted rate of USD 750/hour. The whore expected me to worship her. Boring and a waste of $$.