We've already told you about Amazon's price-saving application in our holiday-helper roundup. The software allows you to use your iPhone's camera to scan the barcode of a product and compare prices from hundreds of Amazon resellers.
But the online retailer also offers a standalone iPhone app that allows you to compare prices: PriceCheck. It gives you multiple ways to search prices to make sure you get the lowest one. And on December 10th it can save you even more money...