Mont. Code Ann. § 2-2-204

2-2-204 . Dealings in warrants and other claims prohibited. The state officers, the several county, city, town, and township officers of this state, their deputies and clerks, are prohibited from purchasing or selling or in any manner receiving to their own use or benefit or to the use or benefit of any person or persons whatever any state, county, or city warrants, scrip, orders, demands, claims, or other evidences of indebtedness against the state or any county, city, town, or township thereof except evidences of indebtedness issued to or held by them for services rendered as such officer, deputy, clerk, and evidences of the funded indebtedness of such state, county, city, township, town, or corporation.