What kind of reputation did Muhammad have as a trader?

Answer 1

Mohammed's occupation as a merchant probably helped him most strongly in the managerial aspect of being a religious and political leader.

Answer 2

Yes. He adopted this profession in his youth. He worked for Hazrat Khudeeja, a wealthy woman merchant of Mecca. Later on he married her.

Answer 3

According to Sirat an-Nabi (the Biography of Prophet Muhammad), Muhammad worked as a merchant for his wife Khadijah's business until he became a Prophet at around 40 years old.