How discount calculator Works
Why 50% + 20% is not 70%
Sequential discounts multiply: $120 → 50% off → $60 → extra 20% off → $48, a total of 60% off. Stores present "extra 20% off" additively because the additive framing (70%) sells better than the multiplicative reality (60%). The math is not deceptive — the framing is.
The price-per-use decoder
A discount's value depends on use: 40% off a $200 coat worn 100 times is $1.20/wear; 40% off a $200 gadget used twice is $60/use. The unit-price habit — applied to clothes as cost-per-wear and to everything else as cost-per-use — defeats the "but it was on sale" justification better than willpower ever will.
The anchoring trap
"Was $299, now $99" works because the anchor sets the value perception — even when the item was never sold at $299. The defenses: check price history (camel-style trackers), compare against the actual alternative you would buy at full price, and decide the budget before entering the store. Discounts change when to buy, rarely whether.