Apple ID only valid for use in Zimbabwe

While you are in Zimbabwe and your Apple ID is set to Zimbabwe you appear to be browsing a store from another country. Which is why you get that message.

This usually happens when you follow a link from the web that directs to an item only available in a specific country that is not your own.

To reset your store to the Zimbabwe store, sign out of your Apple ID, and then sign back in.

Settings->Account(top of settings)->Media & Purchases->Sign Out, then repeat the process to sign back in. You may need to reboot the iOS device before signing back in however.