Section 39-18-105 - Exemptions(a) Sales of cigarettes to any agency of the United States government, sales in interstate commerce or the taxation of any transaction prohibited by the United States constitution are exempted from the provisions of this article but shall be reported to the department in the manner prescribed by it. (b) The sales and use tax exemptions specified in W.S. 39-15-105 and 39-16-105 are not applicable to this article.