A governmental unit may adopt a fee structure for system products that will: make system products available at a cost consistent with the requirements of this subtitle; and cover the cost of providing the system product and an additional charge of no more than $50. A governmental unit may sell system products to the general public for a fee that reasonably reflects the cost of providing the system product. A governmental unit: may reduce or waive the fees that it charges for system products that are to be used for a public purpose; and shall apply its reduction or waiver of the fees uniformly among persons who are similarly situated.