[odonata]

You WILL need to inform you bank that you are using your cards in Japan. All Japanese banks I have used had no problem changing my money. ATMs that will accept your card will be harder to find outside Tokyo. If you are planning a trip outside a major city then carry plenty of cash. You will not be robbed or mugged.
The cost of living can be cheap or expensive depending on the individual.

Never ever ask a Japanese person to speak english "ego ga hanasemasu ka?" as this is a very offensive phrase. better to excuse yourself "Domo sumimasen".