I frequently receive promotion from Northwest Airlines. Their price is pretty cheap!
Look at this one:
Basically, they are saying that
Shanghai, Beijing or Guangzhou to Tokyo round trip: 1750 RMB or 245 USD
Shanghai, Beijing or Guangzhou to LA, SFO, Seattle, Portland round trip: 2690 RMB or 377 USD
Shanghai, Beijing or Guangzhou to New York, Chicago, and most of other cities in North America: 3650 RMB or 512 USD.
Isn’t that cheap?