go to www.cdnow.com. Type in the name of the artist or group. A variety of selections made by that group will appear. Click on the selection of your choice. If the selection has a "speaker " icon next to it, your selection will play for 30 seconds--no charge.
... most PCs these days have the software already installed that allows you to listen to clips like them - it's called RealAudio or Windows Media player -- your PC will work out which one to use and do the hard work -- all you'll need to do is make sure your speakers are on (or that you have headphones plugged in!)