Mont. Code Ann. § 30-12-307

Whenever any commodity or service is sold or is offered, exposed, or advertised for sale by weight, measure, or count, the price shall not be misrepresented, nor shall the price be represented in any manner calculated or tending to mislead or deceive an actual or prospective purchaser. Whenever an advertised, posted, or labeled price per unit of weight, measure, or count includes a fraction of a cent, all elements of the fraction shall be prominently displayed and the numeral or numerals expressing the fraction shall be immediately adjacent to, of the same general design and style as, and at least one-half the height and width of the numerals representing the whole cents.