The commission shall determine the actual cost of work and any other expenses that may be necessary in conjunction with the work, including the cost of notice and mailing. The city clerk shall forward a statement of the actual cost attributable to the work and a demand for payment of such costs, by certified mail, return receipt required, to the property owner and any mortgage holder, at the addresses provided for in section 92.67 of this chapter. If a municipality performs work, the cost to the property owner shall not exceed the actual cost of the labor, maintenance and equipment required. If the work is done on a private contract basis, the contract shall be awarded to the lowest and best bidder. (2001 Code § 92.70)