What is one quick way to save data on my device?

Turning off auto updates on your device is one great way to save data bundle, here is how;

Android

1. Launch Google Play
2. Tap the hamburger icon (three horizontal lines) on the top-left
3. Tap Settings
4. Tap Auto-update apps
5. Select Do not auto-update apps.

iOS 

1. Tap Settings
2. Tap iTunes & App Store 
3. Toggle the slider on App Updates Off (white).