There is a nationwide sale to Athens, which will allow you to visit Santorini or other Greek destinations for 1/3 of the usual price! All you need to do is book the right flight from LAX to Athens, and then use Google Flights to search for roundtrip tickets from Athens to your final destination. These roundtrip flights could be found for as low as $30 on budget airlines like Ryanair. Just remember that budget airlines charge extra for everything (luggage, carry-on, choosing your seat).
Airport Code: ATH
Airline: Air France
Availability: January – May 2017
Nearby Airports? Yes, there are a few flights from SNA on One World partner airlines for $10-20 more.
Stops: 1 (CDG)
Search Here (Google Flights)
Sample pricing (airfrance.us)