California Code, Penal Code - PEN § 28233

(a) The Department of Justice may, in addition to the fee described in Sections 28225 and 28230, require a dealer to charge each firearm purchaser a fee in the amount of thirty-one dollars and nineteen cents ($31.19).

(b) Moneys received by the department pursuant to this section shall be deposited in the Dealers' Record of Sale Supplemental Subaccount, within the Dealers' Record of Sale Special Account of the General Fund, which is hereby created, to be available, upon appropriation by the Legislature, for expenditure by the department to offset the reasonable costs of firearms-related regulatory and enforcement activities related to the sale, purchase, manufacturing, lawful or unlawful possession, loan, or transfer of firearms pursuant to any provision listed in Section 16580.

(c) The fee described in subdivision (a) may be increased at a rate no more than any increase in the California Consumer Price Index as compiled and reported by the Department of Industrial Relations, but not to exceed the reasonable cost of regulation to the department.