I am trying to book a flight for August from Boston to SFO and I am having a hard time with the price. The dates are somewhat flexable (around Aug 1 to Aug 15) but it needs to be a flight with no stops. I checked using Kayak and the cheapest price was $541 on Jett Blue. Are there other websites I can check for cheaper airfares? We fly at most once a year so I don't realy know where else to check besides kayak and travelocity. Any other websites to check would be helpfull.