How to Actually Tell If You're Getting a Deal
A lot of retail pricing relies on the fact that most people won't do the arithmetic in the aisle or the checkout page. Three quick calculations cover almost every situation.
Sale prices
The Discount Calculator finds the final price and amount saved from an original price and a percentage off, with a slider for quickly testing different discount levels — useful during multi-day sales where the percentage changes daily.
Comparing sizes and brands
The Price Per Unit Calculator compares two products by their true cost per ounce, gram, or whatever unit applies, which is the only fair way to compare a small expensive box against a large cheap one. Store shelf labels sometimes show unit price, but not always in comparable units — this fixes that.
Subscriptions
The Subscription Cost Analyzer shows the true yearly and five-year cost of a monthly subscription, and calculates the exact savings of switching to annual billing — the kind of number that makes "just $9.99 a month" look very different over time.