By using a few reputable websites, such as RetailMeNot. RetailMeNot and Coupon Cabin are two of the most popular coupon websites. Like RetailMeNot, Coupon Cabin also provides a Chrome extension and app to notify consumers of deals. Coupons.com, Groupon, Slickdeals, Offers, Dealcatcher, and Coupon Chief are a few examples.