PPC and CPC are often used interchangeable within the advertising community, however generally speaking PPC is used to describe the type of advertising program you are running. CPC, which stands for cost-per-click, is usually used in communicating what you are actually paying per click within your advertising program. To use appropriately in discussion you may say, "We want to run a PPC Advertising Campaign with Google and we want to average our CPC at $0.75." The CPC cost is set by a Bidding process.