Delta and Air France have round-trip flights from Atlanta (ATL) to Istanbul (IST) for $630-$641 with a connection. Flights March, April, October, and November. Departures on Monday, Tuesday, Wednesday, and Sunday. 7-day minimum stay required. No Thanksgiving dates.
A Carry-on bag and also a personal item is allowed for free on Delta. You can avoid paying for seat selection by accepting the randomly assigned seat at the gate.