Isekai Shounin: Skill "Isekai Tokou" wo Kushi shite, Yuuyuu Jiteki na Okanemochi Slow Life wo Okurimasu

One day, the protagonist Allen, who has been reincarnated from Japan into another world, realizes that his unique skill, Moon Gate, allows him to travel freely between Japan and the other world. With this power, Allen comes up with the idea of traveling between Japan and the other world and making money by selling various items to people from the other world, those who have been transferred, and those who have been reincarnated, who are hungry for entertainment! Before long, he gets to know the daughter of a large company and the princess of a kingdom in the other world, and enjoys the other world to the fullest...!!

(Source: Futabasha, translated)