The question is very small, but if I explain the whole issue on this business about male prostitute, escort, massuer and gigolo business, it will be a large article.
Making it small. The usual way of advertiseement these days are through web sites. there are some people write comments on sex stories too. You can see some suspicious ad in paper like 'electrician, can work on electronic apliance at home'. And in area basis there are some similar ad in small card board on tree or lamp post too. The people who understand the meaning, they will get from there. Word of mouth is a big way of advertising too.
A lot run the business through agency, money is good and commission is also good to pay off. The people who runs independant are not as protected as agency as law authority knows about the business they dont bother the agencies.
Unmarried girls dont look for, its usually rich aged woman, even middle calss unsatisfied woman. A lot of business woman grab one from escort agency when they are on business trip too.
Its a good money business, but the life time is very short.