There are 2 major airports in Tokyo, Narita and Haneda (Haneda 1 & 2). Haneda is nicer than Narita. My first visit to Japan in 1995, I landed in Narita. It was not so bad back then as it was relatively new. Today, not so much so. Lawson's is always a welcome site for the weary traveler. This store is near the bus pick up area.
Chocolate Covered Potato Chips (not exactly a huge hit in Japan)