My parents heard from other people that it is always cheaper to get tickets to China from the various web sites. I don't think that is always true. I think if you browse the web sites every day for some period of time (3 months, for example), you might hit some cheap tickets. But in general, they are about the same. you might have to invest a lot of time to find the cheaper tickets online.
That is from my experience. What do you think? thanks for sharing.