The discount is applied once buy enough of what is qualified. I think it is like $50 minimum. Then, you can add non-qualified stuff to the cart and get the discount. I think the limit is, the discount on non-qualified product can't exceed the purchase amount of the qualified product.
So if you just hit the $50 minimum, you can't buy a $500 box of Padron sticks and get the full percentage discount. You would only qualify for a max discount of $50.