(1) All sales to the United States government and to the state of Colorado, its departments and institutions, and the political subdivisions thereof in their governmental capacities only shall be exempt from taxation under the provisions of part 1 of this article.

(1.5) All transactions specified in section 29-4-227 (1), C.R.S., are exempt from taxation under the provisions of parts 1 and 2 of this article.

(2) There shall be exempt from taxation under the provisions of part 1 of this article all sales that the state of Colorado is prohibited from taxing under the constitution or laws of the United States or the state of Colorado and all retail sales within a distance of twenty miles within the boundaries of this state to persons resident, excluding corporations, of adjoining states, which adjoining states do not impose or levy a retail sales tax on such sales, if the residents of the adjoining states are in this state for the express purpose of making purchases and not as tourists.

(3) There shall be exempt from taxation under the provisions of part 1 of this article all sales and purchases of commodities and services under the provisions of section 39-26-102 (11) to any occupant who is a permanent resident of any hotel, apartment hotel, lodging house, motor hotel, guesthouse, guest ranch, trailer coach, mobile home, auto camp, or trailer court or park and who enters into or has entered into a written agreement for occupancy of a room or accommodations for a period of at least thirty consecutive days during the calendar year or preceding year.

(4) All sales made to schools, other than schools held or conducted for private or corporate profit, shall be exempt from taxation under the provisions of part 1 of this article.

(5) There shall be exempt from taxation under the provisions of part 1 of this article all transactions specified in section 39-26-104 (1)(b)(I) in which the fair market value of the exchanged property is excluded from the consideration or purchase price because the exchanged property is covered by section 39-26-104 (1)(b)(I)(A) or (1)(b)(I)(B), and in which, because there is no additional consideration involved in the transaction, there is no purchase price within the meaning of section 39-26-102 (7).