Calculate sale prices and savings with percentage discounts, additional coupons, and bulk purchases. Perfect for shopping, retail planning, and budget management.
Product or service base price
Number of items to purchase
Coupon, loyalty discount, or additional promotion
20% off $100 item
30% off + $10 coupon, 2 items
25% off + 5% additional discount
15% off, bulk purchase
Whether you're hunting deals on Black Friday, Cyber Monday, or Amazon Prime Day, understanding how discounts actually work helps you spot real savings from marketing gimmicks. Let's break down real shopping scenarios you'll encounter at Target, Best Buy, and online retailers.
iPhone 15 Pro
Original: $999
Deal: 15% off + extra $50 store credit
Calculation:
Step 1: $999 × 0.85 = $849.15
Step 2:
= $799.15 final (save $199.85!)
Target Seasonal Item
Cost to store: $40
Goal: 30% profit margin
Retailer math:
If profit = 30%, cost = 70% of price
= $57.14 (retail tag)
Amazon Prime Deal
Item: $200
Prime 10% + $20 coupon
Order matters:
First discount: $200 × 0.9 = $180
Then coupon: $180 - $20
= $160 (you pay)
⚠️ Reversed order gives different result!
🚫 Common Scam
Regular price: $49.99
Week before sale: "Worth $99.99"
Sale day: $99.99 → 50% OFF = $49.99
Looks like 50% off, actually same price!
✅ How to Spot It
This is one of the most dangerous shopping myths. Discounts multiply, they don't add!
Example: $100 item with "70% off TWICE"
Actual calculation:
First 70% off: $100 × 0.3 = $30
Second 70% off: $30 × 0.3 = $9
(Total discount = 91%, not 140%!)
Wrong assumption:
$100 - 70% - 70% = -$40 ← Impossible!
The Math:
= $100 × 0.3 × 0.3 = $9
| Original Price | 30% Off | $50 Off | Better Deal |
|---|---|---|---|
| $100 | $70 | $50 ✓ | $50 off wins |
| $200 | $140 ✓ | $150 | 30% off wins |
| $500 | $350 ✓ | $450 | 30% off wins |
😵 Bad Deal Example
You need: $85 worth of items
Minimum for $20 off: $100
So you add: $15 filler items
Net: Spent $15 to "save" $20 = only $5 real savings
✅ Smart Approach
You need: $98 worth of items
Add $2 useful item (socks, snacks)
Net: Spent $2 to save $20 = $18 real savings
Rule: Only "spend to save" if added items cost less than the discount.
Scenario: "An item is 25% off and costs $60. What was the original price?"
Scenario: "What's the total discount if I get 20% off, then another 15% off?"
Total discount = 32% (not 35%!)
General formula for n discounts:
That "great deal" you found? There's a good chance it was engineered by a pricing algorithm. Here's how retailers use behavioral economics to make you spend more — and how to fight back.
When you see "Was $199.99, Now $99.99", your brain automatically uses the original price as a reference point. Retailers know this — some inflate the "original" price specifically to make the discount look bigger. The FTC actually has rules against fictitious pricing, but enforcement is tricky.
The math behind perceived savings:
A higher anchor always makes the same sale price look better — even if the anchor was never a real selling price.
Amazon adjusts the prices of millions of products up to 2.5 million times per day. Their algorithm considers your browsing history, competitor prices, inventory levels, time of day, and even whether you're on mobile or desktop. That "price drop" you see might have been preceded by a quiet price increase last week.
Nobel Prize-winning research by Kahneman and Tversky showed that humans feel losses roughly twice as intensely as equivalent gains. When a retailer says "Sale ends tonight!", they're not just creating urgency — they're triggering your fear of losing the deal, which is psychologically more powerful than the excitement of saving money.
Research in behavioral pricing found that prices ending in 9 increased sales by an average of 24% compared to rounded prices. Your brain reads left-to-right and anchors on the first digit — so $19.99 feels like "nineteen something" rather than "basically twenty."
Learn more about smart shopping and consumer protection from these authoritative sources:
Tip: Always verify discounts against price history. Use browser extensions like CamelCamelCamel or Honey to track price changes over time.