SimilarWeb - SimilarWeb.com is a website analysis tool that gives you analytics information for any website.
RetailMenot - The RetailMeNot mobile app allows you to find deals on the go for both online shopping and in store shopping.
Website Informer - Website.informer: complete data lookup & free aggregated report on any domain including whois, visitors, IP & DNS details, competitors, owners, etc
Honey - Honey is a browser extension that automatically finds and applies coupon codes at checkout with a single click.
Site Rank Data - View historical rank information of websites via time series charts.
Slickdeals.net - Slickdeals: The Best Deals, Coupons & Discounts on everything