Pay driver
a driver for a professional auto racing team who, instead of being paid by the owner of his car, drives for free and brings with him either personal sponsorship or personal or family funding to finance the team's operations
A pay driver is a professional race car driver who is hired because of the driver's wealth rather than his or her talent. Pay drivers are often the heirs to large corporations and buy their way onto top teams. Hiro Matushita, the son of the founder of the Panasonic Corporation, was a famous example of this in the 1990s. Today, Paul Menard is a pay driver in NASCAR.