Try
matrix.itasoftware.com
It is a little more complicated than Amazon, but far more powerful.
The airports in the immediate Los Angeles area are LAX, BUR, LGB, SNA, & ONT.
At the moment, Delta has the least expensive connection flight, and Lufthansa & United have the least expensive directs.
Virgin does seem to announce wonderful sales though, so I'd keep a close watch on them.
Probably best not to buy now, but to wait for a good sale. Then act immediately. Lots of discussion here on the topic, but some people (me included) feel the dip in rates tends to come around 2 to 3 months before a flight.
Romelle