AliPrice - AliExpress Price Tracker app lets you track the price history of any item from many online retailers like AliExpress, Daraz, and Amazon, etc.
Groupon - Each day Groupon offers a deal through local vendors in your city.
Price Tracker for Amazon - Price Tracker for Amazon is a shopping app that allows you to browse for favorite products from famous online stores know as Amazon for a better price.
idealo - Idealo is a free to use mobile application that helps you to find products, compare price and make an informed decision.
PriceGrabber - Get the lowest prices on computers, electronics, furniture, cameras, clothes and more.
Slickdeals.net - Slickdeals: The Best Deals, Coupons & Discounts on everything