CPI or CPM
CPI stands for cost per impression. This means the advertiser pays each time the advert appears on the publisher’s page. The most common way of referring to this model is CPM or cost per thousand impressions (the letter M is the Roman numeral for a thousand). This is how a campaign is normally priced when brand awareness or exposure is the primary goal.
CPMs for Rich Media adverts are usually higher than for standard media adverts. This is often based on file size.