RCW 19.290.150: License plates—Fee.

The licensee shall obtain a special set of license plates in addition to the regular licenses and plates required for the operation of such vehicles. The special plates must be displayed on vehicles owned and/or operated by the licensee and used in the conduct of the business. The fee for these plates shall be five dollars for the original plates and two dollars for each additional set of plates bearing the same license number. A licensee with more than one licensed location in the state may use special plates bearing the same license number for vehicles operated out of any of the licensed locations.