Honey - Honey is a browser extension that automatically finds and applies coupon codes at checkout with a single click.
RetailMenot - The RetailMeNot mobile app allows you to find deals on the go for both online shopping and in store shopping.
Invisible Hand - InvisibleHand gets you the lowest price on shopping and flights.
Slickdeals.net - Slickdeals: The Best Deals, Coupons & Discounts on everything
DontPayFull - DontPayFull.com serves over 3.5 million visitors with coupons, offers and discounts each month.
Groupon - Each day Groupon offers a deal through local vendors in your city.