This is fascinating! And, yes, it's very different in a country where prostitution is still illegal. In America we have one other category of sex worker, slotted between the street-worker and the escort service.

These are indivuals who advertise their services either in the papers or online. "Personal massage with relief" is the most common code for it, although you can also find brothels advertising that way. A client will call up, make an appointment, and then visit them in a motel room or in the worker's home (yes, very risky). Although there are quoted rates for time, the worker will usually try to negotiate increased fees for different acts, or draw out the experience and suggest that the client might want to purchase more time.

I'd love to see some links in the fic section, if possible.