Bonds issued under sections 447.45 to 447.50 must be issued and sold as provided in chapter 475. If the bonds do not pledge the credit of the county, city, or hospital district as provided in section 447.48, the governing body may negotiate their sale without advertisement for bids. They shall not be included in the net debt of any municipality, and are not subject to interest rate limitations, as defined or referred to in sections 475.51 and 475.55. If the bonds do not pledge the credit of the county, city, or hospital district as provided in section 447.48 and are payable from rental payments to be made under a lease agreement entered into pursuant to section 447.47, the county, city, or hospital district may invest or deposit, or authorize a trustee to invest or deposit, any proceeds of the bonds, rental payments, and income from the investment of them, in any manner and upon any terms and conditions agreed to by the lessee under the lease agreement, resolution, or indenture, notwithstanding chapter 118A, but subject to any statutory provisions that govern the deposit and investment of funds of a lessee which is itself a governmental subdivision or agency.