This deal is back again. Order delivery straight from the KFC app and add a Zinger Stacker Burger to your order to get the delivery fee waived.
If you want to add cheaper chicken pieces to your order try this hack:
Add "Colonel's Dinner" meal to your order. You will then get offered 4x Chicken Pieces for $6.95. Once you add to your order simply remove the "Colonel's Dinner" meal from your cart before you checkout.
There is also some cheap large side offers in the "Build your own Bucket" tab like 2x large sides for $5.95 or 4x large sides for $9.95