Ringtone Maker is the best app for Android smartphones. It lets you create custom ringtones, notification sounds, and even ringtones for individual contacts. You can use your own music, and you can choose from the built-in music library or from your device.

You can create and assign ringtones to specific contacts. This lets you get a notification when someone calls you, and you don't have to look at your phone to see who is calling.

You can choose from the built-in music library or from your device.

The best part of the app is that it is completely free. There are no hidden costs, and you don't have to pay a penny to use the app.