Abstract: A method and system for placing a purchase order with a product trader for a product over a communication network comprises accessing an information site on a shopping server using a shopping client and downloading program code for executing a shopping cart to the shopping client from the shopping server. The programme code when executed on the shopping client generates a purchase order interface for the user enabling a user to input product selection data and payment data. Order data is generated using the received selection data and payment data and at least the payment data is encrypted. The order data is then transmitted from the shopping client over the communications network to a location for reception by the product trader.