RetailMenot - The RetailMeNot mobile app allows you to find deals on the go for both online shopping and in store shopping.
API to bot - Convert your API to Alexa skill or Google Home app in 5 mins
Slickdeals.net - Slickdeals: The Best Deals, Coupons & Discounts on everything
Jovo - 🗣 Build cross-platform apps for Alexa and Google Home
Honey - Honey is a browser extension that automatically finds and applies coupon codes at checkout with a single click.
Voice Principles - Guiding principles for voice design, all in one place