When I worked for now nearly defunct big box mall store famous for its catalog in shipping and receiving, I had an inventory control device that allowed me to see both the wholesale price that the store paid for items along with the retail price that they were sold for. Markups are obscene.

My favorites were the sunglasses. The generic ones cost the store about a dollar each and sold for $20-40. They were shipped in the same box, from the same factory, as the fancy designer ones "made" by vacuous reality TV women. They were almost indistinguishable except for the logos. They cost the store $2-5 and sold for $80-300. It boggled my mind.

Also, no matter how crazy on sale something is, it's never less than the store paid.