Odds are waiting for the fare to drop is futile. I went twice LAX-EZE in 2002 and paid $560 including tax the first time and $520 including tax the second time. I got a sub-$600 fare for Rio as well in 2002, and that was during Carnivale. I'm always checking aa.com, but during all of 2003 I did not see AA offer anything under $800 before taxes. Seems like all of deep South America has been pricey for a long time.