How To Merge MP3s Using Audacity
“Audacity is an easy-to-use, multi-track audio editor and recorder for Windows, Mac OS X, GNU/Linux and other operating systems.
Developed by a group of volunteers as open source.” ~ Audacity
Open the program and drag the music files you want to merge into the Audacity window. Then go to Tracks in the top menu of the Audacity program, then choose Align Tracks, and Align End to End.
You’ll notice in my example that the bottom track shifts to the endpoint of the top one. Then, it’s just a matter of clicking on File, then Export, and Export as MP3.