Each applicant for a permit under the provisions of sections 229.300 to 229.370 may be required by the county highway engineer to pay a fee in an amount determined by the county commission by order of record, not to exceed the sum of seven dollars for each such application, which fee is to be paid into a special fund in the county treasury and to be used for the purpose of paying the expenses incident to the provisions of sections 229.300 to 229.370. Any balance on hand in such fund at the end of the fiscal year of such county shall be paid into the special county road and bridge fund of such county.