All lands to be purchased or exchanged under authority of this chapter must be appraised by the existing appraisal agencies of the parties to the contract and in all cases when there are no such appraisal agencies the board of county commissioners shall determine the value thereof. In no case may lands be purchased for more than their appraised value, nor may any lands owned by the state or the several counties be exchanged except for lands of an equal appraised value.
N.D.C.C. § 55-04-02