Probably the best reasons for visiting Narita-shi on a layover are the temple and the restaurants along the shopping street leading away from the station. Both will require a few hundred to a thousand yen. I am with jib71, just take out the minimum from an ATM, pay cash for the train, coin locker, any entrance fees, a nice lunch and then spend off any remainder at the airport before going to the lounge. Most of the airport businesses have charity donation boxes for leftover coins. The hassle of trying to save $20.00 or whatever the minimum withdrawal is is just not worth it.