Any county owning any public building and site is, except as otherwise specifically provided by law, hereby authorized to sell such building or building and site, when the board of county commissioners shall by resolution determine that such building or building and site is no longer of benefit to the county, upon such terms and in such manner as the board of county commissioners may deem to be in the best interest of the county. Moneys received from the sale of any such building or building and site may be placed in a special building fund and used without regard to the limitations prescribed by the budget law, for any of the purposes authorized by this act and may be used in combination with other funds as hereinbefore provided by this act.