A person engaged in the business of offering individual storage units for rent, or a mini storage operator, shall pay the general license fee required under subsection 3-1-7B of this title and, in addition to that fee, for each storage or mini storage unit over thirty (30), he shall pay an additional fee of five dollars ($5.00) per unit, with a maximum of three hundred dollars ($300.00) as total license fee. (2003 Code)