You should expand the service (or start a new one) into other categories of physical goods: manga, novels, video games, figurines and other merchandise not found anywhere else outside of Japan.

Let subscribers pick their preferred categories and allow them to choose the amount of money they want to pay each month + shipping costs,

then you go out and buy random things from one or more of those categories (in order of user preference), and keep a record of which items you sent to each customer, to avoid duplicates.

Social fluff: Let users post on-site reviews of the items they receive from you.

Ideal outcome: People discover the uniqueness of Japan, share it with their friends and other users, and you help spread some joy and pocket the change.