PROBLEM TO BE SOLVED : To provide a sales promotion system for a sales inventory such as an apartment house stocked in a real estate supplier, and an object or the like with an unsunny aspect of high sales risk in the same apartment house block.SOLUTION : The real estate objects such as the apartment house are formed into a database, cash, a giveaway or the like is restored proportionally to a purchase amount, to a purchaser, and the sale of the object is promoted by this manner.COPYRIGHT : (C)2006, JPO&NCIPI