How to change the Google Play account in Pokemon Go to use the balance?
Solution 1:
I found a rather stupid solution -- remove all other Google accounts except account 1, i.e. the one used for playing Pokemon Go. Hope to see a better solution.
Solution 2:
Found the answer elsewhere. You need to uninstall the app on your phone and install it using the correct account FROM THE PLAY WEB STORE. On your computer. After I did that I had the correct account when I made purchases from the Pokemon Go shop.
I didn't have to remove any of the other accounts on the phone. I am using a different account to pay for purchases than I am for playing pokemon go.