The board of university and school lands may sell original grant land either for cash or under contract. The highest bidder for any tract of land offered for sale under this chapter must be declared the purchaser thereof. A purchaser under contract shall pay twenty percent of the purchase price at the time the contract is executed; thereafter annual payments must be made of not less than six percent of the original purchase price. An amount equal to not less than three percent per annum of the unpaid principal must be credited to interest and the balance must be applied as payment on principal as credit on the purchase price. If the purchaser fails to pay the amount required to be paid at the time of sale, the commissioner or other person conducting the sale may reoffer the tract for sale immediately, but no bid may be received from the person failing to pay as aforesaid. Any person refusing or neglecting to make such initial payment after purchase shall forfeit an amount equal to ten percent of the purchase price or final bid to be recovered for the benefit of the fund to which the land belongs by civil suit in the name of the state.