Fly from New York to Buenos Aires for $603 roundtrip on Avianca. Aregentina doesn't go on sale very often. This price is well below the normal rate and much lower than from anywhere else in North America.
For example, I found seats departing New York JFK on Wednesday, September 12, returning from Buenos Aires EZE on Wednesday, September 19.
Other dates are available for travel from September through November.
Need a room in Buenos Aires? Here's what's available for the above dates on Hotelwatchdog.