In his 25th of age, the Prophet (PBUH) worked in trading with Khadieja’s money ( Khadieja – May Allah be pleased with her- who became later his wife, and is his 1st wife).
Ibn Ishaak said:” Khadieja bint Khuwailed was an honest rich woman who used to pay for men to travel for her in her trading. Quraish – the Prophet’s tribe – were working in trading, so when Khadieja heard about Muhammad’s honesty and good manners, she asked him to work for her and travel with her trading to Ash-Shaam ( now known as all Syria, Jordan Lebanon and Palestine) and paid for him more than anyone before with a servant called Maysarra.
When Muhammad (PBUH) came back from his mission in Ash-Sham, he used to trade in the markets of Makkah or other neighbor markets; such as Ukadh, Majnah and Thalmajaz.
Muhammad (PBUH) didn’t spend his days long only in trading; he worked to offer himself a good proper life. He spent the rest of his time in imitating and thinking about the world, the universe around him and the creator of all these things.