does it depend on how far (considering gas prices)? how far would you go (or really, how much would you spend)?
does it depend on who the person is? or how well you know them? or whether or not you've had sex before? or how good it was if you've had sex with them before? or if the experience will be something unique or special? what would it take?
is paying a lot of money just to travel and have sex with someone a form of prostitution?