WooCommerce Coupon Box is a plugin that helps you to allow your customers to subscribe their email for coupons. This video shows you how to install the plugin and configure it to works as you want.
Free Version: http://bit.ly/woo-coupon-box-free
Premium Version: http://bit.ly/woocommerce-coupon-box
Demo: http://new2new.com/?item=woo-coupon-box
not optimized for mobile