Is it cheaper to fly home from the same city I arrived in?

Technically, yes, the base fare is lower. However, when you factor in the cost of a domestic flight or a 20-hour bus ride back to your starting point, plus the loss of two days of your trip, open-jaw is significantly cheaper.

Can I book separate airlines for each leg?

Yes, but use the 'Multi-city' tool to bundle them if possible. If you book them separately, ensure you have a minimum of 6 hours between arrival and departure if you need to clear customs and re-check bags.

Booking Open-Jaw Flights for South America

Use the 'Multi-city' search tool on airline websites or aggregators to book your inbound and outbound flights as a single itinerary. This prevents the need for expensive one-way tickets and simplifies proof of onward travel for border control.

Define your route. Don't try to backtrack. Choose two different major hubs—for example, fly into Lima (LIM) and out of Buenos Aires (EZE). South America is massive; picking points that move in a logical geographic line saves you 10+ hours of transit time.
Select the 'Multi-city' tool. On sites like Google Flights or airline portals, toggle the trip type from 'Round-trip' to 'Multi-city'. Do not search for two separate one-way tickets, as this is almost always 30-50% more expensive due to airline fare-class rules.
Check the flight duration and connections. South American airports are often hubs for regional carriers. If your flight requires a layover in a city like Bogota or Panama City, ensure the connection time is at least 3 hours to account for potential regional airline delays.
Verify your 'proof of onward travel'. When you book open-jaw, ensure your second flight confirmation is printed or saved offline. Immigration officers in countries like Peru or Chile frequently ask to see proof that you are leaving the continent, not just the country.

Is it cheaper to fly home from the same city I arrived in?: Technically, yes, the base fare is lower. However, when you factor in the cost of a domestic flight or a 20-hour bus ride back to your starting point, plus the loss of two days of your trip, open-jaw is significantly cheaper.
Can I book separate airlines for each leg?: Yes, but use the 'Multi-city' tool to bundle them if possible. If you book them separately, ensure you have a minimum of 6 hours between arrival and departure if you need to clear customs and re-check bags.