i like to use my credit card because i get airmiles on my jal card
but for small purchases i use cash
now i dont mind using my credit card but b4 i overspent a few times
im a little more conservative with my spending now

also in japan, sony and some other companies have introduced Edy which is a prepaid card that can be used in some convenience stores and retaurants
in fact it is spreading quite rapidly
i dont know so much about it but some people have Edy mobile phones and i saw one girl getting a drink from a coca-cola vending machine with her phone a couple of months back and to tell the truth it looked a bit tedious

one guy i know told me he uses the card because it saves him having to deal with small change
the convenience store closest to hi house employs this system
he has the card version rather than the mobile phone