If a pharmacy directly bills the department or an entity with which the department contracts for a drug supplied to a person receiving benefits under s. 49.68, 49.683, or 49.685 and prescribed for treatment covered under s. 49.68, 49.683, or 49.685, the person shall pay a $7.50 copayment amount for each such generic drug and a $15 copayment amount for each such brand name drug.