Free MP3 Cutter and Editor is a simple audio editor which, despite its name, works with both MP3 and WAV files.
The program is a little short on features, but then it's not targeted at power users, rather it's all about concentrating on the basics: trimming unwanted audio, tweaking volume, or converting your chosen audio to mono or stereo.
That aside, though, Free MP3 Cutter and Editor works much like any other audio editor, so you'll feel home right away. After opening a file, you'll see the waveform of that particular song. You can select a particular region of the tune in a mouse click or two, then perhaps delete it with a click.
And once you've finished, the program will then save your work to an MP3 or WAV file. Which does at least give it one additional function: you can use it to convert files between the WAV and MP3 format.
It's basic in the extreme, but if you're just looking for an easy way to trim MP3 files then Free MP3 Cutter and Editor could be ideal.