I was... years ago I had a student from GW stay at my home for free in exchange for sex 1 a week. No money was exchanged, just free room and food. That was a SA.
What's the difference between giving money or paying his rent directly to his landlord?
You're exchanging $ for intimacy. Maybe the guy is not an escort, but he's certainly escorting.
http://2.bp.blogspot.com/-cMwt_70nFrE/UPr0GXuqMqI/AAAAAAAABMk/5ZrPpVvDoh0/s1600/03.jpg