You've probably stumbled into such deals which are intended to convince shoppers to buy something they might not need because they are terrified of losing out on great deals. If you see something like "40% off" and you've got less than two days before the deal expires . . . While I must "limited time" deals can save you money unless you need what's being sold at that precise moment then it's best to keep your money in your wallet and wait. Odds are you'll find similar deals elsewhere at some other time.