What is the cost of sale (COS) metric?

Cost of Sale (COS) is the cost that the retailer has for buying traffic divided by the amount of sales that the traffic generates. If you divide your earnings by your sales for a CPC retailer, this will equal the Cost of Sale metric for your traffic to this retailer.

Example: You drive $100 in sales to a CPC retailer and get paid $12 based upon your number of clicks and CPC rate. The COS for your traffic is 12%.