Mich. Comp. Laws § 801.254

Sec. 4. The sheriff or friend of the court shall disburse the wages or salary of an employed prisoner for only the following purposes in the order stated: (a) Board of the prisoner; (b) Necessary travel expense to and from work and other incidental expenses of the prisoner; (c) Support of the prisoner's dependents, if any; (d) Payment, either in full or ratably, of the prisoner's obligations, acknowledged by him in writing, or which have been reduced to judgment; (e) The balance, if any, to the prisoner upon his discharge.