Yes, most of these apps are compatible with Android and iOS phones. Just be sure to check the compatibility of the app with your phone model before downloading.
Yes, some apps like Audiko allow you to create your own ringtones from your favorite songs. You can choose the segment of the song you want to use as ringtone and customize other settings according to your preference.
Most apps offer free ringtones, but some may also offer in-app purchases for premium ringtones. Be sure to check the details before downloading a ringtone.