Mich. Comp. Laws § 445.106
It shall be an unlawful trade practice for any employer, directly or indirectly, by itself or through a subsidiary agency owned or controlled in part by such employer, to purchase any goods, wares or merchandise in the name of or on the credit of such employer, or at special discounts available to such employer, for any other purpose than for use or resale in the regular course of business of such employer; to sell, cause to be sold, or have under his or its control for sale to his or its employees or to any other person, any goods, wares or merchandise not offered for sale by such employer in the regular course of his or its business; to authorize or permit his or its name, credit or premises to be used in connection with the sale or offer for sale of any such merchandise and to authorize any of his or its officers, agents or employees, during working hours or on his or its premises, to perform any of the acts hereinabove in this section described. This section shall not apply to purchases by an employer for the purpose of use or resale to his or its employees of equipment, tools, candy, chewing gum, meals, tobacco or food services provided in the regular course of business; or to any goods, wares or merchandise which may be related to the business of the employer and which the employer so purchases for resale to his or its employees for the purpose of promoting a principal business of the employer, or for utilizing a principal product or service of the employer. It shall not apply to purchases by an employer for the purpose of resale to his or its employees of automobile safety seat belts for personal use by the employees.
MCL 445.106