In media, a CPM is a unit of cost measurement meaning "cost-per-thousand." The M is the Roman numeral meaning 1,000.

In digital media, you will see orders and rare cards priced on a CPM.

For example, a $4/CPM display order means you are paying $4 for every 1,000 ad impressions served.

Therefore, a campaign of 22,000,000 impressions at a $4/CPM will cost you $88,000 total.

See the handy Clickz CPM calculator.