(1) Unless otherwise provided by law, a county may not purchase real property in an amount in excess of $20,000 or a conservation easement using public funds in an amount in excess of $80,000 unless the value of the property or conservation easement has been previously estimated by:
(a) a disinterested certified general real estate appraiser selected by the county commission, county attorney, and landowner; or
(b) three disinterested citizens of the county appointed by the district judge.
(2) A county may not pay more than the appraised value for the real property or conservation easement.