Promo code ANDROIDPAY is valid for $10 off one trip taken by May 31. I had no problem adding it to my account.
Using the Uber app just click ‘promotions’ in the menu tab to add this. On the Uber website you can add the promo code on the payment page. Update: To use the code successfully you may need to pay for your ride using Androidpay.
Of course if you haven’t used Uber before you can get a free ride, different signup codes vary. Lately individual referral links have only been good for $15 while some companies have made deals with Uber for $20 referral links.
My referral link for Uber seems to be giving a bigger first-time rider credit than it used to, up to $25:
(HT: The Forward Cabin)