Pay-per-click is commonly associated with first-tier search engines. With search engines, advertisers typically bid on keyword phrases relevant to their target market and pay when ads (text-based search ads or shopping ads that are a combination of images and text) are clicked. There are different types of PPC ads, but one of the most common types is the paid search ad. These ads appear when people search for things online using a search engine like Google – especially when they are performing commercial searches, meaning that they're looking for something to buy.