What makes something seem like a good deal? Subtle ways of framing the same information can make your students more compelled to purchase. Which sounds better 25% off or $5 off? Most people see the numbers and not the % and $ signs and act accordingly. When is 20% off better than $150 off?
Every day, you are bombarded by discounts. Show your students how they are being manipulated and that should always “do the math”.