This is the link to the documentation
http://www.abantecart.com/ecommerce-documentation/31-admin-user-manual/catalog-menu/products#Options%20TabCheck out the 'Promotions Tab - special price information for this product here.' for details.
There are two areas - one for discount one for specials (or sale prices)
Again, I would encourage you to read the entire documentation manual - it will take you only a little while, but you will learn how things work and it will make your working on your cart much faster. There is a learning curve with every new application one starts use.
If you used the search box in the Documentation - it brings up 4 places and one of them is products - and it would have taken you directly to the link I posted above.
Keep at it - your cart is looking good
Lee