In online advertising, there are various evaluation and billing models for
the efficiency of online ads. In addition to the frequently used cost-benefit ratio for clicks, the costs per click (CPC), there are several more differentiated evaluations. One of these is the cost per order, cost per order (CPO). Costs per Order, also referred to as Costs per Sale
(CPS), includes the direct costs of online advertising incurred per order or for a sale made. CPO costs can be equally derived from ad costs for banner advertising or AdWords and are directly related to the amount of order costs. In the case of the costs per sale, the turnover for the individual order is relativized by the cumulative turnover.