The bar prices in Narita hotels are HIGH. You can buy beer at the local supermarkets for a fraction of the price, or go to some of the local bars that are numerous, far cheaper.
The only exception is if you fluke Happy Hour in the hotel bar. This makes some drinks reasonably priced.
OK... This is what I would call an airport tourist trap. I really don't reccomend buying things and gifts at the shops at the airport. everything is extremely expencive, even postcards. So if you have the oppertunity to buy things in Tokyo only use the airport to buy water and food (oh and Sushi!), or you will find your self poor at the airport :(
Unique Suggestions: Only buy necessities. Don't go buying last minute gifts, its way too expencive.
Fun Alternatives: Buy all your Japanese stuff in Tokyo, not at the airport.