Google Play Store lets you turn off auto-play videos

The Google Play Store, particularly in the Games feed, auto-plays video for promoting certain games and apps. Now, you can turn off this feature if you're worried about it eating up your data. Head to Settings > General > Auto-play videos. There are three options there: one will auto-play videos at any time, another is over Wi-Fi only, and then the other turns the feature off entirely. This feature doesn't work with GIFs, those still work on auto-play. You will have this option if you have version 17.9.17 of the app.

Source: 9to5Google