score:3
I faced this problem some time ago: one-way rental in Turkey. I started out with the obvious internaitonal rental companies, which usually have good networks, as well as some specialised. They were all quite expensive.
Eventually I rented the car via a local travel agency, I found via TurkeyTravelPlanner. I was really happy about it. A good quality service for a fair price. They even brought the car to the hotels.