There's a food hall in the basement. For more information see the Mitsukoshi web site. Odakyu You'll find a big branch of Odakyu on the west Side of Shinjuku Station - it's owned by the Odakyu Railway Company. Prices are mid to high. Seibu, Tokyu and Keio These department stores are owned by railway companies.
Prices are reasonable.
You'll find a big branch in Shibuya.