People going to Ephesus are often ripped off by an exorbitant taxi or transfer from Izmir airport. You can avoid this by taking the train from Izmir Airport to Selçuk. There aren't many trains; they depart the airport at 8.01, 9.38, 15.32, 18.39, 19.34, 20.12 and 21.33 and take 1 ¼ hours. The alternative (if you don't have much baggage) is to walk to the end of the airport slip road (about 1 mile), cross the main road and pick up a minibus.
The train station is right next to the airport and well signposted. The train fare is 2 Lira (80p), the minibus is 6 Lira (£2.50). If you need to get a taxi, you might be able to haggle the price down to 80 to 100 Lira (£30 to 40).
Updates
Check the car park opposite the terminal exit and look for Turkish Airlines or Havalaani (airport) coaches. These give cheap transfers to their respective offices in Izmir. Not always there (mainly when a Turkish Airlines flight arrives) but worth looking.
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