I am happy to help you. If you need clarification with this answer, hit reply and ask a follow up question prior to providing a rating. Otherwise, after reviewing the answer, please provide a positive rating without additional cost to you so I receive credit for the services I am providing you.
You can trademark a name or a logo. So, yes, a trademark can be used as a company name (e.g., Hershey and Hershey bar). It does not matter if you use a different name for your company or product, except that if you want to protect both names, you would have to trademark both names.
For an on line site offering both product and services, you would have to get a trademark for the product and a service mark for the services. The name can be the same but the categories in which you trademark the names would be different.
Feel free to ask follow up questions before providing a rating. This information provided to you is informative and helpful. If you need clarification, feel free to hit reply so we can work on any clarification prior to providing a rating. Otherwise, please provide a positive rating now without an additional cost to you so I receive credit for the services I am providing to you. I am doing my best to help you. Thank you, Damien