Barnett Brass sells economy door knobs for $15 each. Unit product costs are as follows: Direct materials $3 Direct labor 2 Manufacturing overhead 4 Total $9 An order to purchase 4,000 units was recently received from a new customer. There is enough capacity to fill the order and filling this order would not disrupt current operations. Barnett Brass would incur an additional $1.50 per unit for shipping costs. Thirty percent of the manufacturing overhead costs are fixed and would be incurred no matter how many units are produced. In negotiating a price, how much is the minimum acceptable selling price