Exactly. $400 for a half hour of lying on your back will seem like easy money to these girls. They've done it for free many times before. Beats getting a job at Micky D's.
She can make an extra $400 - $500 if she lets her "John" take pictures, which will end up on an internet porn site.
Substitute any number of drugs for the sex and you have yourself one more career choice for today's sophomores.