Cost Per Thousand 

Cost per thousand, also known as cost per mille, it is a marketing term which is used to denote the price of 1,000 advertisement impressions on the one webpage. If a website publisher charges $2.00 CPM, which means an advertiser must pay $2.00 for every 1,000 impressions of its ad. The "M" in CPM represents "mille," which is Latin word for "thousands."

 Cost Per Click 

Also called as pay-per-click (PPC), cost per click (CPC) is defined as a method which websites use to bill based on the number of times a visitor clicks on an advertisement. The other alternative is cost per thousand (CPM), which is the number of impressions, or viewers, in thousands, regardless of whether each viewer clicks on the advertisement or not.