I am in the process of booking a hotel in Athens (Hera) and I have the option of reserving a transfer to and from the airport (50 Euro each way). Is this a cost effective option? What other transportation options are there? We will be getting in late from Santorini (around 930 pm) and will be leaving around 830 am.
Between 5am and 11pm the one-way taxi fare is fixed at €35 and taxis are easily found out at the airport. Be sure to set the price with the driver to avoid any shenannigans. If you're just going to spend the night and catch a flight out in the morning why not stay out by the airport and save all that money? Check Peri's Hotel and the St. Thomas B&B. They offer free airport pickup and return. from 7am-11pm.