A tax is imposed on marijuana and controlled substances as defined in Code Section 48-15-2 at the following rates: (1) On each gram of marijuana, or each portion of a gram, $3.50; (2) On each gram of controlled substance, or portion of a gram, $200.00; and (3) On each ten dosage units of a controlled substance that is not sold by weight, or portion thereof, $400.00. History. Code 1981, § 48-15-6, enacted by Ga. L. 1990, p. 1231, § 1. 48-15-7. Time of payment of tax; report forms.