It's not exactly cheap, but pzizz is worth the price. I've tried a few guided meditation/relaxation CDs and audio files, but in the end, the fact that an audio track is the same every time you listen to it makes a huge difference—kind of a relaxation burnout. The beauty of pzizz is that every single napping session it generates is truly different. This magic is effected by a very sophisticated algorithm that assembles various audio elements on the fly, and it does an absolutely superb job: you may recognize the occasional phrase (spoken by a pleasant and soothing male voice that you can optionally disable if you wish) from different naps, but the experience pzizz produces never has a "stitched-together" quality. The differences are subtle, but the benefit is huge; every nap sounds fresh and original. You can set various parameters and save them for specific types of naps (duration, relative volume of voice relative to ambient sound, the time for the "waking up" phase, etc.) for different occasions, but even then no two of the naps generated according to your parameters will be the same (this does not apply, of course, if you chose to export your naps as audio files, which will essentially be nothing but a recording). When I feel washed out in the middle of work, I turn to pzizz for a soothing power nap of 15 minutes and wake up quite refreshed—it's gentler on your heart than a cup of espresso, too!