The freebie products are defined in this section.
For each product, the following details are show, of which some are
Item code: The item code of the freebie product is placed
in the text field. A product with the given item code must exist (the backing
product). The itemcode must also be for a product that is specific, e.g.
a single option choice if the product has option(s).
Purchase price: The purchase price of the backing
Product price: The selling price of the backing
Product can be removed from the campaign with the "X" button.