My friends and I are going to Japan for 10 days, 12 if you count time on plane to and from. We're going to Tokyo, then Kyoto and Osaka. I assume a JR Pass is the best option but when I look around I'm seeing different sites selling them and the prices are wildly different. My question is A. do you know the cheapest site? And B. is there a reason why some are way pricier than others?