You can easily customize your android phone with your favorite ringtones. You can record the sound that may be from a room or a singing tone and make it your ringtone. If you already have a music collection, then you probably need a single app to get your work started. You need to download Ringtone maker and install it, and yes, it is absolutely free.
You will find a list of music, now you can search for your favorite ones and can make it your ringtone. For this, you will have to tap the ‘green arrow icon’ present on the right side.
Here is a detailed description how you can install custom ringtone on your android phone: