The practise of having sexual relations in exchange for cash is referred to as prostitution and is also called "the oldest profession in the world."
The real meaning of prostitution, however, goes far beyond than that. In addition to streetwalkers, prostitutes are also those who operate in brothels.
A fine and up to life in prison or a minimum of 10 years in jail are the penalties for transporting someone under the age of 18 with the aim to use them as a prostitute[ii].
Prostitution has been a contentious issue since the founding of the US. The majority of states currently prohibit it, however there are a few where it is permitted.
"Prostitution is only permitted in authorised brothels in these counties. Prostitution is not permitted in a few of counties in Nevada, nevertheless.
State laws differ on how prostitution is punished. Some jurisdictions classify soliciting for prostitution, engaging in prostitution, and agreeing to engage in prostitution as misdemeanours.