An indicia encoding system is disclosed herein that encodes integrated information on products and/or services selected for purchase and payment information for purchasing the selected products and/or services, in accordance with a variety of embodiments involving various methods, devices and systems. In one illustrative embodiment, a method may include entering purchase order information via one or more input/output components. The purchase order may include an indication for one or more products and/or one or more services. The method may also include entering payment information, including information on a method of payment, via one or more input/output components. The method may also include generating a machine-readable indicia that encodes both the purchase order information and the payment information, with the payment information in an encrypted form; and displaying the machine-readable indicia on a screen.