A free app for Android, by ShamiTech Apps.

Best MP3 Cutter – Ringtone Maker is a simple, easy-to-use music editing tool for Android that lets you easily cut, trim, copy, paste, and merge audio files. With it, you can create your own unique ringtone or notification tone and save it to a folder on your device or share it with your friends and family.

It supports MP3, WAV, OGG, FLAC, AAC, AIFF, and more audio formats. It also has a built-in music editor and a music library so you can choose from your own music and trim, cut, copy, paste, and merge it with other files to create a new audio file.