Kyla,
You bring up another good point, which is that escorts are not negotiable whereas SBs are, and if there is a chemistry and connection with the SB, from my experience the negotiation goes heavily in favor of the SD. I have done trips with SBs where all I paid them for was the equivalent of one hour of intimacy with an escort, although also paying for their meals, hotel, and entertainment (e.g. Empire State Building tickets, museum tickets).
I am taking a SB with me on a trip next week. I am not paying her anything, and the deal is we are going as friends, and I will buy her meals, pay for our lodging, and also any activities we do (bike rentals, movies etc.) She left up to me whether I want intimacy, if I do it's $300 per each time we are intimate. I doubt I will, we do it when I feel like it, otherwise she is fine getting together as friends for no pay. The guys posting in this thread do not understand that relationships like this do get born on SA. Many times. Which is why some of Fradi's posts drive me bananas. He eliminates the possibility that you can meet someone, have sex with them and you actually become friends. The term "friends with benefits" exists and sometimes accurately describes what the relationship is.