Cost per 1000 Impressions (CPM)

The number of times an ad is shown. M is Roman numeral for 1000.
If your budget is say $10,000 then mean your ad will be shown 1,000,000 times ($10,000 *(1000/$10)

Cost Per Click (CPC )

Google Adwords made this model popular. For example:

  • If the CPC is $1.00 and your ad is shown 12,000 times but gets no clicks then you pay nothing.
  • If you get 10 clicks on your ad then you pay $1.00X10 = $10.00