MP3-jPlayer is completely free software. The easiest way to get MP3-jPlayer is to install it through your WordPress Dashboard, it’s very quick to do:
1) Log in to your site and go to Plugins > Add New
2) Search for mp3-jplayer
3) Click Install Now next to the plugin’s name in the search results
4) Once WordPress has installed it click Activate
Alternatively, to install the plugin manually you can download the zip file at wordpress.org from the following link:
Unzip the download and copy the inner folder called ‘mp3-jplayer’ to your plugins directory on your server, alternatively you can upload and install the zip file via your dashboard.