How do you define "it works" ? The price of a user is defined by the following formula [0] : CPU = CPC * (C / U) Google AdWords gives you the CPC and if you h

How do you define "it works" ? The price of a user is defined by the following formula [0] : CPU = CPC * (C / U) Google AdWords gives you the CPC and if you have a Google Analytics set up you should be able to know the C / U ratio. That will define how much you have to pay to get a user using Google AdWords. For the C / U ratio to be precise you should use only the organic search numbers (people coming to your website from Google after a search) because it is closest behavior you can study. [0] : * CPU : Cost per User * CPC : Cost per Click [on ad] * C : Click [visitor comes on the website from ad] * U : User [visitor becomes a user after he clicked on the ad]