Advertising Costs can only be deleted if they are not in use. Any Cost currently in use can only be Deactivated to remove it from future use, as historic data is dependent upon it's existence.
If you wish to delete a cost that is in current use, you will first need to remove it from the campaigns where it is in use.
To Delete A Cost
You must be an Administrator to delete Costs
Click on your company name in the upper right corner of Bionic.
Click on the Administration option
Click on the Costs Columns tab
Use the check boxes to select the Costs you want to delete
Press the Delete button
Removing A Cost From Use
Each Cost will display the number of campaigns that are currently using this cost. If the Cost is in use, you can click through on this number access the Cost Allocations.
From here, click on the Cost to see a list of campaigns that use this cost.
Click through to each campaign to remove the Cost from the Settings, or change the Cost being used.
Once the Cost has been removed from all campaigns, you can use the process above to delete the Cost.