Not easy unless you are Turkish. I spent a month there a few years back and it is limited. There are a few red light districts that are government sanctioned but they are real sketchy. Turkey is a great country but prostituition is heavily policed, in the coastal tourist areas you can find russian and bulken free lancers inn bars but they are usually linked to organized crime so all in all it is a poor country to be a hobiest. Take the midnight train to bulgaria and it is great hunting grounds.