Click on 'Manage Inventory' under the 'Inventory' heading in the Control Panel menu. Then, use the 'Search' tab to find the item.

Click 'Edit' below the item.

Go to the 'Pricing' tab. Next to 'Discount,' specify the amount using the dropdown menu. Then, click 'Save Changes.'

To remove the discount, return to this screen and change the discount amount back to 'None.'