I am here teaching now, I don't think there's a foreign teacher at my school who isn't making twice as much they are spending. Then again we get free housing, so we have one less expense to worry about.
Basically it is like this:
Housing - probably as expensive as Japan
Produce - probably more expensive then Japan (if you buy it fresh)
Beef - probably a little less expensive then Japan but still expensive
All other store bought food - cheaper then Japan
Eating out - A LOT cheaper then Japan
Entertainment - A LOT cheaper then Japan (4 dollars to see a baseball game that is every bit as good as what you see in Japan for example)
Electronics - a bit cheaper then Japan
Outside of those areas you would have to tell me separately, that's most of what I know about. So as a whole a lot cheaper then Japan, but then again housing is probably the main thing you are wondering about (unless you are about to teach or get another job with free housing) and that's about the same.