RetailMenot - The RetailMeNot mobile app allows you to find deals on the go for both online shopping and in store shopping.
Honey - Honey is a browser extension that automatically finds and applies coupon codes at checkout with a single click.
Invisible Hand - InvisibleHand gets you the lowest price on shopping and flights.
Slickdeals.net - Slickdeals: The Best Deals, Coupons & Discounts on everything
DontPayFull - Verified coupons and discounts for a variety of online retailers.
Capital One Shopping - Get the best coupon code, the best price, and alerts when items you viewed go on sale.