American Airlines has a decent sale for travel between Atlanta and Santiago de Chile.
This also presents an opportunity for a Hidden City ticket. As the trip is via Miami one could build in a long connection in Miami and forget to take the last segment. You need to collect luggage in Miami on your return and if you don't do it often you won't be penalized.
So add a cheap First segment to Atlanta and build some time for a connection in Miami where you can check-in your luggage for the Chile flight and then on the return just collect bags and keep walking! The savings are significant MIA-SCL is $3190 versus $1657 so over $1500 in savings for adding a positioning flight.
American Airlines 777 Business Class