Download a rap beat loop. A loop is a sample of a beat that is only a few seconds long. Go to 20DollarBeats.com (see Resources) and choose an option from the side menu. This includes Free Beats, Battle Beats, West Coast Beats and more. Click the "Play" icon beside the track to preview and click the "Download" link to download the track.
Open Audacity. Go to the top menu and select "Project," then "Import Audio." Browse for the rap beat loop and select "Open."
Repeat the loop. Go to "Edit," "Select" and "All." Click "Effects," then "Repeat." Enter the number of times to repeat and click "OK." The length of the track will be listed under the number of repetitions.
Add effects. Go to the "Effects" tab and select an option. Choose to change the pitch, add bass boost, delay and much more.
Save the track. Go to the "File" tab and select "Save Project." Enter a file name and click "Save."
Export the track. Go to the "File" tab and select "Export as MP3." Enter a file name and click "Save." To export an MP3 track it is required to have the Audacity Lame MP3 Encoder installed. Go to the Guides and Tutorials website (see Resources) to download and install this encoder if you do not have it already.