Abstract: A trading support server for items of a virtual space: stores a seller who wishes to put up a sales item, the sales item, and an individual price, causes the seller to declare a parent item used to create the sales item, and stores information identifying the parent item, determines whether a parent item is associated with a specific item, and where a parent item is associated with the specific item, adds individual prices of the specific item and the parent item to a charged amount, and adds the individual price of the specific item to a sales amount of a seller of the specific item, and the individual price of the parent item to a sales amount of a seller of the parent item where the purchaser has paid the charged amount having the individual prices of both the specific item and the parent item added.