$219 - Flights to LA from Chicago
The Cheapest JetBlue flights are Monday-Wednesday and Saturday. They just announced a specific deal to Long Beach Airport that will be no longer available after August 5th (this coming Wednesday).
The cheapest United flights are on Tuesdays, Wednesdays, and Saturdays, and you usually need to book at least two weeks in advance. Flights on other days can cost 50 to 100 dollars more.