Manga Sozai Saishuka No Isekai Ryokouki

Takeru Kamishiro is an ordinary middle aged salaryman who was chosen by god to be reincarnated into a fantasy world in the body of a handsome young man in his prime. Takeru sets out to learn more about the world while gathering rare and interesting materials along the way to sell for money which he can use to gather even more materials ad infinitum.