R.I. Gen. Laws § 11-19-9
All schemes and devices by which any person or corporation shall sell, give, or distribute any stamp, trading-stamp, cash discount stamp, amusement stamp, check, coupon, or other similar device to any purchaser of goods, wares, or merchandise, which will entitle the holder of the stamp, trading-stamp, cash discount stamp, amusement stamp, check, coupon, or other similar device, on presentation of it, either singly or in definite numbers, to receive either directly from the vendor or indirectly through any other person or corporation, some indefinite and undescribed article, the nature and value of which are unknown to the purchaser of the goods, wares, and merchandise at the time of the purchase of the merchandise, are declared to partake so much of the nature of a lottery as to be detrimental to the public morals, and are declared to be illegal.
R.I. Gen. Laws § 11-19-9