Hello,
A discount field will automatically appear within your cart whenever there is a discount available for that item. If it is not there, then no discounts in our account could be applied to that purchase. Did you remove or change any discounts recently?
If you can't resolve the problem feel free to email us your discount information at support@e-junkie.com so that we can go into your account and double check your discount settings (and via email you won't have to worry about posting the discount info publicly).