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 an Opt-In List, Building Relationships
If you aim for success, you must do everything within your means to achieve that. You just donÃt go on sitting there in your house complaining about not getting as much profit as you expect.

