In campaigns targeted to the search network, a cost per click (CPC) bid is set for each ad group or keyword in your pay per click management campaign. The CPC bid is the amount you are willing to pay for a click on your ad when it appears on Google or one of our partner sites.
With pay per click marketing campaigns targeted to the content network, you have the option to make it a CPC bid of a cost per thousand impressions (CPM) bid for each ad group, keyword or placement. The CPM is the amount you are willing to pay each 1,000 times your ad appears on one of Google’s partner sites. You pay when your ad shows, no matter if a user clicks on the ad or not.
With CPC and CPM pricing, you’re in control of your bids. With AdWords, it will help keep your costs down to a bare minimum using AdWords Discounter and Smart Pricing.