Hi,
Thank you for your post and giving us an opportunity to assist you.
Its possible that the settings are incorrect for your location and this is causing the currency to show incorrectly on the Store App.
You can change the settings by following these steps.
a)Type "Region" on the Start screen, click "Settings" and press enter.
b)On the "Format" tab, select "English (United Kingdom)".
c)Click "Languages Preferences" > "Add a language" and add "English (United Kingdom)".
d)Once added, select it and click "Move Up" to make it the first language. Close the Language window.
e)On the "Region" window, click "Additional Settings" and check if the values are British.
f)Click the "Location" tab and change the Home Location to "United Kingdom" and then click OK.
Feel free to use the forum for any other Windows questions you may have.