Retailers often get better deals if they order more of the same item. For example, the cost per unit for t-shirts might be $7.50 per unit if less than 48 pieces are ordered; $7.25 per unit if 49-72 pieces are ordered; or $7.00 per unit if 73 or more pieces are ordered. Depending on the quantity discount, all pieces ordered must be delivered and paid for by a certain date, or the purchases and payments can be spread out over a specified period of time