Cal. Bus. & Prof. Code § 17751

“Trading stamp” also means any stamp or similar device issued as a gift or as a consideration in any transaction other than in connection with the retail sale of merchandise or service, by a trading stamp company that also issues those devices in connection with the retail sale of merchandise or service, as a cash discount, or for any other marketing purpose, and that may be redeemed by the rightful holder on the same basis as, or interchangeably with, any trading stamp issued as described in Section 17750.