Leviticus 25:14-17

If you make a sale, moreover, to your friend or buy from your friend’s hand, you shall not wrong one another. Corresponding to the number of years after the jubilee, you shall buy from your friend; he is to sell to you according to the number of years of crops. In proportion to the extent of the years you shall increase its price, and in proportion to the fewness of the years you shall diminish its price, for it is a number of crops he is selling to you. So you shall not wrong one another, but you shall fear your God; for I am the LORD your God.