How much you spend to win a single paying customer. Cost per acquisition (CPA) is a marketing success metric that can be calculated for a campaign, a digital marketing channel (such as email), or across all channels and tactics. At a campaign level, the formula is: total campaign cost / conversions (paying customers) = CPA. This metric is commonly used to determine the results of display ad and affiliate marketing campaigns.

Building and managing an opt in list for a website
Building and managing an opt in list for a website provides a seller direct access to a wide number of potential customers. Building and managing