The purchaser of state-owned tidelands or shorelands, otherwise permitted under RCW 79.125.200 to be sold, except in cases where the full purchase price is paid at the time of the purchase, shall enter into and sign a contract with the state to be signed by the commissioner on behalf of the state, with the seal of the commissioner's office attached, and in a form to be prescribed by the attorney general, and under those terms and conditions provided in RCW 79.11.200.