Disclosed are a mobile shopping agent and a shop agent seller for reducing negotiation burdens between a seller and a buyer. The mobile shopping agent detects the shop agent's entrance to a radio access area of a personal area network (Bluetooth, ultra wide-band, and Zigbee), requests shop goods information of desired goods from the shop agent through the radio access area of the personal area network when the shop agent has entered the radio access area, and receives the shop goods information. The mobile shopping agent requests online goods information on the desired goods from a goods information server through a communication network, and receives the online goods information. The mobile shopping agent determines a buying condition of the desired goods based on the shop goods information and the online goods information, and negotiates with the shop agent by using a game theory.