A computer-implemented method of performing an interactive valuation of a saleable commodity, such as a real estate property, said method comprising : receiving one or more descriptors to allow for identification of said saleable commodity; retrieving valuation data corresponding to one or more comparable saleable commodities; presenting to a user said valuation data corresponding to each of said comparable saleable commodities; enabling said user to rank said saleable commodity relative to said comparable saleable commodities based upon said valuation data; and assigning a listing value to said saleable commodity based upon the ranking of said saleable commodity by said user. START ] Receiving one or more descriptors to allow for identification of vendor' s property , l Retrieving valuation date corresponding to one or more comparable real estate properties Presenting to the vendor valuation data corresponding to each of the comparable properties , l Enabling the vendor to rank their property relative to each of the comparable properties l Assigning an agreed listing value to the property based on the vendor' s ranking of the property FIGURE 2