Discounts presets will save you time and effort. Presets can be made for FTP, Veterans, Friends and Family, you name it. To create a preset:
From your menu:
You will be presented with a new window, here you will give your discount a name (FTP, Veterans, etc) and the amount of the discount. Please note that you can either do a percentage or a dollar amount. Click save.
Now your budtender will be able to see the discounts at check out.