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Now that you are a private pilot with an instrument rating, several people want you to fly them places for business or pleasure, and they are willing to pay you for that time. But according to the FAA you cannot be paid for these flights unless among other requirements, you are a commercially rated pilot.
A commercial pilot may be compensated for flying. Training for the certificate focuses on a better understanding of aircraft systems and a higher standard of airmanship. A commercial airplane pilot must be able to operate a complex airplane, as a specific number of hours of complex (or turbine-powered) aircraft time are among the prerequisites, and at least a portion of the practical examination is performed in a complex aircraft.