I keep getting sent to the wrong store after finding the app I want to purchase

Hi,

What to do before changing your country or region

1. Spend any store credit remaining on your Apple ID. You must also wait for any pending store credit refunds to process before you can change your country or region. Learn what to do if your remaining store credit is less than the cost of a single item.
2. Cancel any subscriptions, including Apple Music, and wait until the end of the subscription period to change your country or region. You'll also have to wait for any memberships, pre-orders, iTunes movie rentals, or Season Passes to complete.
3. Update your payment method. For example, only German credit cards can be used to buy content from the German iTunes Store, iBooks Store, and App Store. Have your credit or debit card for your new country or region on hand.
4. Back up your iPhone, iPad, or iPod touch to iTunes. You might need to temporarily downgrade your iCloud storage until you switch to the new country or region.

Change your Apple ID country or region - Apple Support

Have you moved to a different country?

[Note: the two documents below have been changed by Apple in late 2017 and no longer contain the information quoted.]

App Store [for iOS devices] Frequently Asked Questions (FAQ) - http://support.apple.com/kb/HT2001 when using iTunes --> "To change countries, scroll to the end of the iTunes Store home page and click the flag indicating the current country. To choose a different country, click the appropriate flag."

iOS: Changing the signed-in iTunes Store account - https://support.apple.com/HT204053 - Change your iTunes Store country: "Sign in to the account for the iTunes Store region you'd like to use. Tap Settings > iTunes & App Stores > Apple ID: > View Apple ID > Country/Region." (wording from old document; new document does not contain this information).

Are these in-app purchases? They may be directing you back to the US store if you got the app in the US Store. Just guessing here.