The county board of commissioners in each county is empowered by majority vote of all the members-elect, at any regular, adjourned, or special session of said board, to purchase for their respective counties, the reversionary interest in and to any and all real estate which may have been transferred to said county by deed, dedication or otherwise for public purposes, and to provide for the payment for the same as for other current and necessary expense. Not more than $5,000.00 dollars shall be expended for the purposes of this section, unless authorized by a majority of the electors of such county voting therefor at a general election or at a special election called therefor.