As reported here on The Travel Trickster, you can find some seriously cheap flights from New York-JFK or Miami-MIA and Iguazu Falls-IGU:
Book flights from New York-JFK or Miami-MIA to Iguazu Falls-IGU for as low as $474 to $524 for travel in January, February or March 2015.
How to Get ItHead to ITA Matrix Airfare Search Use the “See calendar of lowest fares” search functionality [...]
Plan a weekend get-away from New York-NYC to Seattle-SEA for under $220! The deal also works in reverse for those wishing to fly from Seattle-SEA to New York-NYC. The fare is from American Airlines (bookable on AA.com) for flights operated by Alaska Airlines.
How to book it:Check http://matrix.itasoftware.com/ using its calendar of low fares to see all availability. There’s great availability all September & October and some in November. Find a few dates that might work, jot down flight times, numbers etc… Head to AA.com, enter the exact dates in a search and select your desired [...]