In Maryland a person may not act or offer to act as a home improvement contractor unless the person has a contractor license.  A person may also not sell or offer to sell a home improvement unless the person has a contractor license or salesperson license.

A person who violates this requirement is guilty of a misdemeanor and, on first conviction, is subject to a fine not exceeding $1,000 or imprisonment not exceeding 30 days or both and, on a second or subsequent conviction, is subject to a fine not exceeding $5,000 or imprisonment not exceeding 2 years or both.

§ 8-601, et, al.  of Business Regulation Article of Maryland Annotated Code Acting as contractor or subcontractor or selling a home improvement without license.