- Effective cost-per-thousand impressions (eCPM)
- Cost-per-click (CPC)
- Viewable cost-per-thousand impressions (vCPM)
- Cost per acquisition (CPA)
If you want to increase brand awareness—not drive traffic to your site—focusing on impressions may be your strategy. You can use cost per thousand viewable impressions (vCPM) bidding to put your message in front of customers.
Read more here: https://support.google.com/adwords/answer/2472725?hl=en