The governing body of the county may call an advisory countywide referendum election on the question of whether or not the qualified electors of the county support or oppose the governing body levying the additional sales and use taxes authorized in this part. All costs of the advisory referendum, including, but not limited to, the cost of publishing the notice and of furnishing ballots or renting voting machines, shall be paid by the county. The governing body of the county shall not be bound by the results of any such advisory referendum and may in its sole discretion determine to levy or not levy the taxes authorized in this part.