I remember my first payday after coming to work as a teacher in Japan, being handed an envelope containing my entire month's salary in cash, which was quite a surprise to me. Japan has always been a very cash-oriented society, with no equivalent to personal checks or money orders, and when making purchases most people will pay in 10,000 yen bills. Credit cards exist here of course, but they're much less common than in the U.S., and to get one you need to pass a strict credit check and have been employed at the same company for at least a year -- a far cry from the pre-approved credit cards I'd get in my mailbox back in college. A few years ago, we bought the plot of land behind our home, I remember going to pay for it in cash, counting out the bills for the previous owner as we finalized the contract. Of course, the only thing constant in the world is change, and Japanese are slowly adopting alternate ways of paying for products, such as Suica, a rechargeable contractless smart card that can be used to pay for train tickets, food purchases and so on. One of the most innovative ideas I've seen in a long time are the cell phone with Suica cards built into them, so all you need is your phone and you can pay for just about anything.
Of course, if you want cash we've got both yen and dollars on J-List.