Honey - Honey is a browser extension that automatically finds and applies coupon codes at checkout with a single click.

AliPrice - AliExpress Price Tracker app lets you track the price history of any item from many online retailers like AliExpress, Daraz, and Amazon, etc.

Invisible Hand - InvisibleHand gets you the lowest price on shopping and flights.

idealo - Idealo is a free to use mobile application that helps you to find products, compare price and make an informed decision.

RetailMenot - The RetailMeNot mobile app allows you to find deals on the go for both online shopping and in store shopping.

Camelcamelcamel - Easily monitor Amazon product prices and get alerts when they drop.