Subject to the provisions of section 4b-30, the Commissioner of Administrative Services may lease state-owned land to private developers for construction of buildings and facilities to meet the needs of agencies and institutions, provided such developers shall agree to lease such buildings and facilities back to the state with options to purchase. Such options to purchase shall give the state the alternative of purchasing such building and facilities for a lump sum at a stated time, or times, during or at the end of the lease term; or to purchase the same by paying the purchase price in specified installments over a stated period of time.