Well I know Walmart, CVS, Best Buy, and Riteaid among others are starting to block NFC payments so both Apple Pay and most likely Google Wallet will not work. look it up in the news. A bunch of stores are coming up with their own technology called CurrentC....
Starbucks does not have NFC registers either so it will not work as NFC payments. So no wireless payment unless you use their app ... Download the app and it will get scanned by their readers.
However Starbucks will allow users to add funds to their app using Apple Pay. The Apple Pay wallet is more than just wireless payments.
It is supposed to be implemented by end of the year.
Also I would not use the term Apple Pay at the stores.. 99% of the people will have no idea what that is as it is just the wallet technology. Registers that allow the NFC chip to pay wirelessly will have this image.
Image
Also a link talking about CurrentC. The other tech is here
https://forums.macrumors.com/threads/1809706/