Abstract: Autonomous operation of a mobile retailing computing system. In one aspect of the invention, an onboard server situated in a public transportation vehicle establishes communication with a plurality of client devices each client device displaying products offered for sale from multiple different merchants and coordinates a purchase transaction in which payment is accepted in exchange for a products from a plurality of the different merchants. Customer information, purchased product information, and payment information is obtained from each of the plurality of client devices. Communication is established with a payment integration server over a wide-area network connection to enable processing of payment transactions with a plurality of different acquiring banks corresponding to different ones of the plurality of merchants.