Delta, Virgin Atlantic, Air France, American Airlines and various other airlines have round-trip flights from New York (JFK) to Athens (ATH) for $503, NONSTOP. Flights September to March. Departures on Monday, Tuesday, Wednesday, and Sunday. 7-day minimum stay required.
A Carry-on bag and also a personal item is allowed for free. You can avoid paying for seat selection by accepting the randomly assigned seat at the gate.