I'd like to avoid unwanted purchases.

You can prevent unintentional or unauthorized purchases by blocking or setting passwords.


<iOS>

Use Restrictions to protect your iTunes Store account.


1. Go to Settings > General > Restrictions.

2. Tap Enable Restrictions.

3. To prevent in-app purchases, turn off In-App Purchases

How to Turn on Restrictions on Apple device

<Android>

Set up authentication within Google Play Store app.


1. Tap the Menu icon > Settings.

2. Tap Require authentication for purchases.

3. Follow the on-screen instructions and choose a setting.

How to prevent unwanted purchases on Android devices