CPM bidding refers to cost per thousand bidding. If you’re wondering where the “M” came from, we have the answer. The number 1,000 is written as “M” when you use Roman numerals, so that’s why you see an “M” and not a “T” in the acronym for CPM bidding.When you use CPM bidding for your paid search marketing, you pay for impressions rather than clicks. That means if someone sees your ad but doesn’t click on it, you still have to pay for the view, and you pay per every thousand views.Paid per click bidding is typically called PPC bidding. Unlike CPM bidding, you only pay for actions that actually occur. If someone clicks on your ad, Google AdWords deducts money from your account.The type of bidding you choose depends on your budget and your marketing goals. CPM bidding is ideal if you want to increase brand recognition. It’s basically the equivalent of saying, “Hey, here I am” and hoping readers remember you later. PPC bidding is best if you have a small budget or intend to convert visitors into subscribers, buyers or applicants after they reach your landing page.If you choose PPC bidding, it’s important to know that costs vary. Your ads might cost more than similar ads, so sometimes it’s difficult to estimate an exact figure when you chat with other marketing professionals. Google establishes per-click costs with an auction-like process where the highest bidder gets the best position on each page.However, a high bid doesn’t guarantee ad placement. If and when a high-bid ad appears, visitors see it near the top of the page. If it doesn’t appear very often, it might be because Google has given your website a low quality score.