The present apparatus is a mobile shopping cart that can automatically keep track of objects selected and carried in the cart and provide a customer using the cart information like the total price of the items carried. The cart has a radio frequency cart base station with a cart antenna connected to a radio frequency cart transceiver. Various novel embodiments of the invention produce a radio frequency field within the shopping cart that is used to communicate with radio frequency tags on objects carried in the cart. The tags contain information about the respective carried object to which the tags are attached. A program function executed by the cart circuit and/or computer controls the cart transceiver to interrogate radio frequency tags within the radio frequency field, i.e. inside the cart to gain information about the carried objects. Tags on objects external to the cart are not interrogated.