From THAI website (press releases)
8. Purchase of Boeing 747-400 from Leasing Company
THAI’s Board has approved the purchase of the second Boeing aircraft 747-400 from aircraft leasing company Emerald Wing Company Limited once the current agreement has expired on 22 March 2002, since the airline still has need for aircraft utilization. The aircraft has been used for 12 years and has an operating life of 20 years. Purchasing the aircraft from the aircraft leasing company will enable THAI to buy the airplane for less than the bid price, at approximately USD 21.15 million dollars.
About as much as a new B717!