The cost of a redevelopment project shall be deemed to include the actual cost of the construction or rehabilitation of any part of a project which may be constructed or rehabilitated by a municipality, including architects' and engineers' fees, the purchase price of any real property that may be acquired by a municipality by purchase, all expenses in connection with the authorization, sale and issuance of bonds or other indebtedness to finance such acquisition, and the interest on bonds for a reasonable time prior to construction or rehabilitation, during construction or rehabilitation and for not exceeding one (1) year after completion of the construction or rehabilitation.