From the Minfos Till, with products added to a sale:
1. In the sales window, click the product that you want to discount, to highlight it.
2. Click Disc. $.
The Product Discount window is displayed.
Note: A product cannot be discounted if it is marked as non-discountable, or if it is a script. Till preferences can be changed to allow private scripts to be discounted.
4. Complete the sale as normal.