I need you to go walk around your closest shopping district looking at displays. Do you see some that are taking advantage of the concept of elasticity? Particularly cross-price elasticity? You see this when you see groups of items used together displayed together. Are all of them on sale or only some of them?
Often enough you’ll see drinks represent elasticity strongly. Think about when you go to City Market and you want a Pepsi, or a Coke but you see a very similar brand made by Kroger with the name changed just a bit in order to not be copywrited. It is the items like these that show their elasticity greatly, why pay $2.50 for a Coke when you could buy a Shasta Cola for $1?
Even so, although the sodas are practically similar, and the taste alike, what companies decide to do as well is market the sodas differently. When you look at the tags of Shasta Cola they’ll say $1.00 in big red letters, and a yellow explosion effect behind it, while normal Coke is just black and white.