Read only access to app store on ios devices
You can use Restrictions to disable the ability to purchase apps or to install any apps.  To turn on Restrictions:

Tap Settings &gt; General.

Tap Restrictions.

Tap Enable Restrictions and create a passcode for Restrictions. Don’t forget this passcode. In the future, you'll need your Restrictions passcode to change your settings or to turn off Restrictions.
What you can restrict

If an app or feature is on or if there's a checkmark next to it, anyone using your device can use that app or feature. Otherwise, no one can use that app or feature.


Apps and features 
Safari 
Camera (also disables FaceTime) 
FaceTime
iTunes Store
Apple Music
Apple Music Radio
Apple Music Connect (replaces Connect tab with Playlists)
iBooks Store
In-App Purchases
Siri
AirDrop
CarPlay (available only with iPhone 5 or later)
Installing apps
Deleting apps
Multiplayer games in Game Center
Adding Game Center friends
You can restrict access to YouTube in iOS 5 and earlier.


Types of content
 - Ratings
 - Music and podcasts
 - Movies
 - TV shows
 - Books
 - Apps
 - Siri
 - Websites

If you don’t use Touch ID for paid and in-app purchases, you can choose between two options for how often you need to enter your password for these purchases.