I have used the service often in both directions, the buses leave fethiye and marmaris every 30 minutes on the hour and half past. I normally walk to gunlukbasi and wait by the pummakale office, they will pick you up here. You can pay the driver on the bus, normally collect money at one of the stops. Last October cost about 20tl. When you get to marmaris there are colour coded dolmus routes into the centre. The dolmus service within marmaris does not like you to take suitcases into the dolmuses.