They always jack up the prices before a big sale to make it look like you're saving more than you actually are.
What are chances that the goods offered at such low prices are genuine? Do we get value for money with such deals?
It varies.
The goal is to maximize total profit.
If I can sell you one thing at below cost, you may buy other things on which I am making a profit---and then we both win.
I've gotten you to spend more at my store, and you have gotten a good deal.
That item I've sold at cost or below is called a "loss leader."
(A loss leader (also leader)[1] is a pricing strategy where a product is sold at a price below its market cost[2] to stimulate other sales of more profitable goods or services. With this sales promotion—marketing strategy, a "leader" is used as a related term and can mean any popular article, i.e., one sold at a normal price.[3]---Wikipedia)
You get what u pay for. Many products are on sale to get u in the doors then u will buy something else so they dont lose money