I Can Always Go Home, So I Started a Merchant Business in Another World

After being overworked in a black company, Shiro Nita quits his job and moves to his grandmother's house. He discovers that his new home is connected to another world and decides to use his skills to become a merchant, trading Japanese goods for the currency of this new world. This is the story of a kind man who uses his equivalent exchange skill to convert the other world's currency into Japanese yen, becoming increasingly wealthy in both worlds. Please note that the web and book versions have different stories and characters.