The term Cost Per Click (CPC) is often used interchangeably with Pay-Per-Click (PPC), though PPC is generally thought of as the advertising model whereas CPC is the specific dollar cost.
It's important to know the difference between the two major PPC types - Search and Display. Search, which displays advertisements within the context of search engine result pages, is a high-intent, higher-cost advertising medium. Display has a broader context in that ads will get seen significantly more but, because user intent is weaker, Click Through Rates (CTR) will be lower. As a result, CPC for Display will be lower than for Search.
It’s important to know what type of visibility or clicks you are aiming for. Are you looking for brand visibility or "ready to buy" users? Make sure you test your messaging and your landing pages and invest the time to improve your quality score (a system Google has developed to reward "good" advertisers).