20 Websites to Find US Promo Codes and Discounts RetailMeNot. One of the most well-known coupon sites is RetailMeNot. ... Coupon Cabin. Similar to RetailMeNot, Coupon Cabin also offers an app and Chrome extension to alert users of deals. ... Coupons.com. ... Groupon. ... Slickdeals. ... Offers. ... Dealcatcher. ... Coupon Chief. More items...