A sales management system includes a first device including a first processor that is configured to detect a customer moving an item of merchandise in an extraction direction away from a merchandise display, a second device including a second processor that is configured to detect movement of an item of merchandise from the merchandise display and determine a movement direction thereof, and a third processor that is configured to determine whether the extraction and movement directions are substantially identical when the first processor detects the customer moving an item away from the merchandise display and the second processor detects movement of an item from the merchandise display at substantially the same time, and determine the item as a first merchandise to be purchased by the customer when the extraction and movement directions are determined to be the substantially identical.