Arafou Otoko no Isekai Tsuuhan Seikatsu

Kenichi, a single man in his 40s, transmigrates to another world while foraging in the mountains, and he gets out of danger by using the special online shopping skill that he was given when he was transferred. With the buy-back function, he can cash in his otherworldly belongings and buy goods from modern Japan. When he started selling those items in the market, they quickly became popular and sold for a good price. He could have continued to grow his store, but Kenichi's goal is to live a slow life. He is happy living self-sufficiently on the outskirts of town, but one after another, trouble arises.

A middle-aged man's mail-order life in another world begins now!

(Source: Tsugikuru Books, translated)