Wash. Rev. Code § 19.83.010
Every person who uses, or furnishes, or sells to any other person for use, in, with, or for the sale of any goods, any trading stamps, coupons, tickets, certificates, cards or other similar devices which entitle the purchaser to procure any goods free of charge or for less than the retail market price thereof, upon the production of any number of such trading stamps, coupons, tickets, certificates, cards, or other similar devices, shall before so furnishing, selling, or using the same obtain a separate license from the auditor of each county wherein such furnishing or selling or using shall take place for each and every store or place of business in that county, owned or conducted by such person from which such furnishing or selling, or in which such using shall take place.
RCW 19.83.010