C.R.S. § 32-9-140

(1) Any securities authorized in this article, except for warrants not issued for cash, and except for temporary bonds issued pending preparation of definitive bonds, shall be sold at public or private sale for not less than the principal amount thereof and accrued interest, or at the board’s option, below par, at a discount not exceeding seven percent of the principal amount thereof, but such securities shall never be sold at a price such that the net effective interest rate exceeds the maximum net effective interest rate authorized. (2) No discount, except as provided in subsection (1) of this section, or commission shall be allowed or paid on or for any security sale to any purchaser or bidder, directly or indirectly.