In most states in US the answer is YES. If the answer is YES then why are escorts and clients busted in sting operations? This answer is very simple. It is all in your actions and what you say.
I know you have seen this statement many many times: " ... any money is for my time only ...."
Is it illegal to ask a date out, spend $200 on wine and dining then both of you decide to have sex? Of course the answer is NO.
If you handed your date the $200 to pay for the date then you later both decided to have sex would this be illegal? The answer again is NO.
SO what is the difference in a date that cost you $200 with the ending result you got lucky or paying an Escort $200 with the ending result you got luck.
The answer is legally not a thing.... They are both very Legal.
Now Lets give another example. You are out on a normal date and playing around you handed your date the $200 and then ask her what you would get for the money? Your date took the money or even just stated you would get 1 hour of hot sex.
If by some chance a cop overheard this jokingly conversation, you both could be arrested for prostitution and solicitation.
Now here is the BIG difference between a "normal" date and prostitution date. It is what you say and or actions.
Listen up guys and gals... DON'T TALK ABOUT MONEY AND/OR SERVICES EXPECTED. At least until both feel confident in each other.