Social Coupon for WordPress is a WooCommerce extension that allows you to easily add a social coupon system to your site that allows users to get instant discounts for sharing your pages. Social Coupon makes it super easy for you to gain thousands of new fans and followers for your brand, and increase your social media traffic. More shares = more traffic = more $$$$
Demo: http://codecanyon.net/item/social-coupon-for-wordpress/3417466