Set Item Price Level to Zero Through Updating Price Level Record

1. Navigate to Setup > Accounting > Accounting Lists (Administrator)
2. Filters: Set to Price Level
3. Click the price level you want to edit.
4. Click Edit.
5. In the Price Level field, you can change the name of this price level.
6. In the Markup/Discount % field, enter: -100.0%
7. Check the Update Existing Prices field.
8. Click Save.

After you click Save, all Item prices for that specific Price Level automatically updates to Zero. User needs to repeat this step for every Price Level they would like to be set to Zero.