Milk and dairy in general plays a minor, much diminished role in the Japanese diet vice-Western food roles, and as such isn't as prevalent as one would think. Quart sized cartons, the biggest milk containers to be normally found at food stores, sold for $5 or $6 USD when I was there in the summer of 2007. Smaller 180ml glass bottles (small cartons are non-existent) sell for about $1.50 USD.