RetailMenot - The RetailMeNot mobile app allows you to find deals on the go for both online shopping and in store shopping.
Groupon - Each day Groupon offers a deal through local vendors in your city.
Slickdeals.net - Slickdeals: The Best Deals, Coupons & Discounts on everything
Rakuten - Feel the Joy of Cash Back. Find coupons and Cash Back in just 1 click with the Rakuten browser extension
Offers.com - Offers.
Marqit.co - Find all the newest deals, coupons & promo codes, track price history and be notified of deals! Worldwide!