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.

Effective Email Marketing
Email marketing is quickly becoming one of the most popular forms of Internet advertising. This is because there are many distinct advantages to the concept