Retailers shall be required to send at least one person to lottery training to be conducted by the commission and/or the lottery operator. All expenses or costs of attendance by employees of a retailer shall be paid by such retailer, including, but not limited to, costs of salaries, travel, lodging, meals, and materials. If employees of a retailer have previously attended lottery training, the commission may not require attendance of such employees. In this event, the retailer shall certify to the commission that at least one employee at the retailer's location has previously attended lottery training. Additionally, the commission may require a retailer to participate in lottery training as determined by the commission.