Only had a few hours during my layover, so headed to Narita (the town) via the train from Terminal 2.

Of course I realized I had my large carryon that I forgot to leave in a locker when I got off the train, but as luck would have it there were lockers right at the Narita train station (well more like a subway - light rail station).

The smallest locker went for 300 Yen, the larger for more. Since I didn't leave my stuff at NRT airport, can't say how the price compares, or if the lockers are available at all stations.