Minn. Stat. § 549.03: ACTIONS FOR SERVICES; DOUBLE COSTS.

When any person who employed another to perform any labor or service neglects or refuses to pay the agreed price, or the reasonable value if there is no agreement, for 30 days after it is due and payment is demanded, and the payment is recovered by action, there shall be allowed to the plaintiff, and included in the judgment, all of the disbursements allowed by law and double the costs.