You can set different CPCs per site for each ad.
- Click the Manage tab
- Click Show Ads link
- Click Edit link next to ad
- Click +Add site CPC
- Enter the Site ID and CPC*
- Click Submit for Review**
*Site IDs can be found in the Detailed CSV available for download on the Reports page
**This change will take place immediately, the ad will not need to be re-reviewed.