Except as otherwise provided no contract shall be made by the governing body and no expense shall be incurred by any department or any officer thereof, whether ordered by the governing body or not, unless an appropriation shall have been previously made concerning such expense, or the governing body has authorized the issuance of bonds for a specific purpose. Any authorization of payment or incurring of obligation in violation of the provisions of this Charter shall be void and any payments made illegal. Except where prohibited by law, however, nothing in this Chapter shall be construed to prevent the making or authorizing of payments or making of contracts for capital improvements to be financed wholly or partly by the issuance of bonds or to prevent the making of any contract or lease providing for payments beyond the end of the fiscal year, however, an appropriation need not have been previously made concerning such future disbursements, except sufficient to cover the amount payable or estimated to become payable under such contract for the first year thereof. The governing body shall annually thereafter appropriate an amount sufficient to cover the amount payable or estimated to become payable under such contract during the ensuing fiscal year.