Вот, что ответил саппорт:

Thank you for contacting Google. The content available in Google Play varies by country, and we use your home address in Google Wallet to help determine which version of Google Play you see.

If you're having issues viewing your country's version of Google Play, please try the following troubleshooting steps (ideally using a browser on a desktop or laptop computer, but the Play Store app works also):

1. Sign into Google Wallet at https://wallet.google.com/ and click Payment methods on the left hand side.
2. Click Remove to any Payment Methods located in Ukraine.
3. Set your US based payment method as your Default Payment method. click the Settings icon in the top-right corner.
4. Click Edit next to the "Home address" listed and update the address (please note this is different from the "Address book" which holds shipping addresses).
5. Open the Google Play website and navigate to any paid item available for download at https://play.google.com/store/apps.
6. Click to begin a download until you reach the 'Accept and buy' screen (no need to complete the purchase).
7. Close Google Play and clear your browser cache if you're on a desktop or laptop computer.
8. Wait 30 minutes.
9. Re-open the Google Play. You should now see the Play Store that matches the country in your legal address.

If these steps don't resolve your issue, you can also try purchasing a paid app and refunding it within the 2-hour return window in place of Step 6 above; however, returns like this can only be done in the Play Store app at this time.

Как я понял, просто так поменять валюту нельзя. Нужно переключать себя на другую страну в Google Play.