The trustees may purchase, own, rent, or maintain emergency medical services apparatus or equipment within the state or outside the territorial jurisdiction and boundary limits of this state, provide housing for such apparatus and equipment, provide emergency medical service and facilities, and may certify for levy taxes as provided in section 357G.8. The trustees may purchase material, employ emergency medical service and other personnel, and may perform all other acts necessary to properly maintain and operate the district. The trustees may contract with any other city or county or public or private agency under chapter 28E for the purpose of providing emergency medical services under this chapter. The trustees are allowed necessary expenses in the discharge of their duties, but they shall not receive a salary.