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.
CoinRebates - Shop at your favorite online stores and earn Bitcoin cashback rewards on your purchases.
Slickdeals.net - Slickdeals: The Best Deals, Coupons & Discounts on everything
DiscountSignal - DiscountSignal helps you earn cashback, rewards and offers for Restaurant, Bar or Cafe receipts.
Dealspotr - Dealspotr is like Wikipedia for deals.