Muteki Shounin no Isekai Nariagari Monogatari: Gendai no Seihin wo Jizai ni Toriyoseru Skill ga Aru node Isekai de wa Rakushou desu

A college student who wandered into a different world with his beloved cat. After discovering the “trading” skill, he decided to grow up in a different world!? He became a merchant and decided to stay in the different world with the knowledge and skill he has! Source: MU