Android Pay just launched a week ago on September 10th, and is already available at a variety of stores. But, in order to use Android Pay, your bank has to support the system. Some banks, such as Wells Fargo and Bank Of America, supported the service on day 1. However, it looks like Google is flipping the switch on other banks that were previously unavailable, such as Citibank.
I just added my card to the Android Pay app and now it works. While Google’s website still lists Citibank as “Coming Soon” it appears to be working right now. So if your bank is Citibank, go ahead and try it out. And you can download the Android Pay app right here.