Uber has partnered with Facebook Messenger to allow you to order rides from the Messenger app. When you order your first ride through Messenger, you will get a free $20 ride credit, even if you already have an Uber account.
“For a limited time, you’ll get a free ride the first time you use this feature (up to $20 value) with Uber. All you have to do to claim your free ride is link your existing Uber account or set up a new account within Messenger and request a ride. Driver status updates and payment receipts will get delivered to a private conversation between you and Uber. With everything in one place, you can seamlessly keep track of your ride and payment history.”
Sounds pretty simple and a nice way to get a free ride. Make sure you update your Messenger app to the latest version to make sure that you can do this.
Here is a link to this promo.