The legislative authority of any county shall have the power to furnish, upon such terms as the board may deem proper, with or without consideration, financial or other assistance to any municipal corporation, or political subdivision within such county for the purpose of implementing the fire protection, ambulance, medical or other emergency services provided by such municipal corporation, or political subdivision: PROVIDED, That no such municipal corporation or political subdivision shall be authorized to expend any funds or property received as part of such assistance for any purpose, or in any manner, for which it could not otherwise legally expend its own funds.