Once you've hooked up with the coffee purveyors network, you will see a landing page that offers a free connection to Google Play Music All Access. The service is limited to Starbuck's U.S. stores and is similar to a promotion it had with iTunes back in 2007. That program allowed users to buy songs from the coffee seller's Wi-Fi network.
Everyone gets a 30 day free trial of the streaming music service. At the end of the free trial, users can decide to subscribe to the monthly service or just drop it. Subscribe before the end of June and the cost will be $7.99 per month. Once the calendar flips to July 1st, the price goes up to $9.99 per month.
source: Google+ via SlashGear