How to buy/update/reinstall Android apps in China or on devices without Google Play Store?

IMPORTANT NOTE: Circumstances change frequently, so we cannot guarantee the following will necessarily work, so please proceed at your own risk!

These instructions cover Buying, Updating and Reinstalling Android apps from within China or on devices without Google Play Store installed. In-app purchases are covered in the Buying section.

Devices without Google Play Store

If your device does not have Google Play Store installed, you will not be able to purchase apps, make in-app purchases or retrieve your purchases made earlier on other devices. Some devices make it possible to install Google apps (e.g. Google Play Store) without rooting your device.

Xiaomi devices make this particularly easy.
For Amazon Fire tablets, read this guide.
For those comfortable with more technically in-depth solutions, you can try flashing OpenGAPPS (more info here).

If you are thinking of buying an Android device in China, then we generally recommend Xiaomi because those tend to be easiest to update with Google apps. Furthermore, some Xiaomi devices (e.g. Mi 5X, and probably the Mi 6X in future) can be flashed with an Android One ROM.

Using Google Play Store in China

If you are in China then you will need to use a VPN (there are many such free apps for Android) to do just about anything with the Google Play Store. The past advice of swapping your SIM card, is no longer relevant.

Preliminary Notes:

for a VPN provider suggestion, please check the VPN section of our FAQ
(not recently verified) if you have a rooted device, then you should be able to avoid needing a VPN by using Market Helper. Alternatively, read this guide
if Google Play Store is not behaving as it should do, check out this topic: Google Play Store Issues & Solutions or contact Google Play Support

Buying

Start your VPN (this is probably all you need to do, but if it's still not working then continue with the steps below)
Clear Data on Play Store app - in App Launcher, long press on Play Store app and drag it to App Info. There you can Clear Data
Run Play Store app to accept Terms & Conditions. Wait a few seconds for the Play Store app to fully load after this
Now you should be able to buy apps and make in-app purchases

Note: If you have already made an in-app purchase and Hanping Dictionary mistakenly thinks that you haven't, then repeat the above steps before using the Refresh button in the top-right of Hanping's Add-ons screen.

Updating

From Hanping Chinese Dictionary Add-ons screen > Apps tab > tap on the app. From here you should be able to view the app in the Play Store app.

Another way is to view our blog from your Android device and then tap on the appropriate Google Play link on the right.

When viewing the app in the Play Store app, if there is an update available, then the install button will be labelled "Update".

Reinstalling

(taken from Google Support)

Using your mobile device:

Open the Google Play Store Google Play Store app
Touch the Google Play Store Play Store icon and select My Apps
Visit the All category
Select an app you'd like to install, then touch the Install button on the app's detail page

Using your computer:

Visit your My Apps page on Google Play
Select an app to view its detail page
Tap the button that says Install or Installed and select the device where you'd like to install the app
Tap Install

Note: When an app shows an "Installed" button on its detail page, it means that the app is installed on one of the devices associated with your Google Account.