Method of buying or selling items and a user interface to facilitate the same

An interactive grid-based graphical trading system for use by any trader, where the system comprises a grid-based graphical interface, said graphical interface being adapted to establish connections with any backend system;

• wherein said interactive grid-based graphical trading system is adapted to receive and display market trading data received from said backend system;
• wherein said interactive grid-based graphical trading system includes first process means that function to send transaction instructions to said backend system, and to receive messages and market trading data from said backend system;
• and wherein said grid-based graphical interface includes second process means that function to receive, process, and display said market trading data, and said messages;
• wherein said market trading data includes information chosen from the group of market trading data consisting of:
• order data of said trader, and quote data for any selected security or group of securities;
• wherein said interactive grid-based graphical trading system includes third process means that function to transform said market trading data into a graphical representation for display on a display device, wherein said graphical representation includes at least one grid having a plurality of cells arranged in a matrix chosen from the group consisting of:
• a plurality of rows and at least one column, and a plurality of columns and at least one row;
• wherein a row is an arrangement of horizontally adjacent cells with at least one common property, and a column is an arrangement of vertically adjacent cells with at least one common property, and wherein each cell within the said plurality of cells belongs to one row and one column;
• wherein said plurality of rows or said plurality of columns are associated with a price axis representing a range of prices, wherein said range of prices is associated with the trading price range of any given security;
• wherein any cell may be associated with said market trading data, and contains a graphical representation of said market trading data;
• wherein each cell along said price axis indicates a price or price range for which said market trading data exists, and the other of said at least one column or said a least one row is indicative of a specific criterion chosen from a plurality of criteria within which said market trading data may be categorized;
• and wherein said any trader can place, or modify, an order for a selected security or group of securities, over which that trader has discretion, by interacting with said grid-based graphical interface.