Wyo. Stat. Ann. § 6-10-105

A person committed to jail for willfully refusing to pay a fine or costs may be imprisoned if the court determines that the defendant has an ability to pay or that a reasonable probability exists that the defendant will have an ability to pay, until the imprisonment, at the rate of fifteen dollars ($15.00) per day, equals the amount of the fine or costs, or the amount shall be paid or secured to be paid when he is discharged.