Mp3 Cutter and Merger is an audio editing tool that lets you crop any audio file that you have on your Android's memory. This way you can create as many ringtones as you want, and save them conveniently to your device.
Using Mp3 Cutter and Merger is really simple: you just have to select the audio file you want to work with, and then cut and paste the fragment that you are interested in. Once you're done merging your audio file, you can play it directly from the app.
Mp3 Cutter and Merger is a great app for two main reasons: it's really easy to use, and it takes very little space on your device's memory (less than 1 megabyte).