Originally Posted by
x1achilles
I did this a few months ago with an ongoing flight to ATH. They direct you to a transit lounge and you never go through passport control, avoiding the visa. If you have a few hours, its worth it to leave the airport and go see the Agia Sofia or Grand Bazaar. Americans only have to pay €20 unless they've raised the fee recently. And its granted on the spot.
Is it now 20 Euros rather than US$20 for USA passports?
In these cases, it's wise to have the exact change in the required currency just in case something happens, such as a missed connection, and you want to use visa on arrival to enter the country.
At IST, the procedure that I've used is to hand your passport and a nice new USA twenty dollar bill to the guy at the visa window. The passport is handed back with the "visa" stamp and you go on your way. Just check that you've received the right passport back.