A single custom formula you can add to your spreadsheet to calculate CPM or cost per mille. You can calculate your cost per views, or cost per units. No matter what the "mille" is. 

The math behind this is to take the amount of views or units and divide by 1,000. Then take the cost and divide it by that. That way you can normalize price even if there's large differences in views and costs.

This add-on and CPM function itself, is great for marketers and analysts. You can use this to normalize prices across many different sources and mediums as well.