While raising sales in the inventory module, you can apply percentage and amount discounts. 

In order to sell a product at a discounted price in the inventory module:

  1. Click inventory in the main left sidebar
  2. Click add sale on the right and fill in the sale form as you normally would (> More on adding sales in the inventory module)
  3. Click add discount:

  4. By default, the discount will be applied to all services and products sold. You can change this by clicking the the drop-down menu and selecting the option selected services and products:

    If you choose to discount selected items, a list of sold products and services will be shown and you will be able to enter discount values:

  5. To change the discount type, click the default percentage sign next to any item, and select the symbol of your currency:

  6. Click save

  7. Once you've filled in the sale form (more information in How to sell products directly in the inventory module), click the complete sale button.