Is camilla Parker bowles a commoner?

Yes she was. However she has royal blood. She is a direct descendant of Charles II from one of his illegetamate children. She also may be the great-grandchild of King Edward VII (the son of Queen Victoria and the great-great grandfather of Prince Charles). Camilla's great-grandmother Alice Kepple was the King's mistress for many years and while she was his mistress she gave birth to a baby girl who many think was the daughter of the king.