From funds available in the solid waste management fund established by § 68-211-821, the department shall offer matching grant assistance to counties for the purpose of establishing or upgrading convenience centers required by § 68-211-851. Such grant funds may be applied to expenses for land, paving, fencing, shelters for attendants, containers and basic equipment including, but not limited to, balers, crushers, grinders and fencing. Such funds may also be applied to expenditures for developing and printing of operating manuals, but such funds may not be used for regular operating expenses of a recurring nature. The local share of the match shall be determined by the department, using an economic index promulgated by the board based upon factors which include, but are not limited to, per capita income and property values of the county applicant. Counties falling within the lower one-half (1/2) of the economic scale on the index shall be eligible for lower matching rates. The board shall promulgate regulations regarding the appropriate index and matching rates.