David Pierce has three hypnosis MP3s at http://www.dpierce.com/trance/hypnomp3.html
They’re about 15 minutes and each is a complete session, with music.
NLP practitioner Michael Beale has a relaxation induction at http://nlp-experts.org/nlp-hypnosis/90-hypnosis-mp3-downloads-free.html, though there’s no music.
The biggest site I found is: http://www.freehypnosistreatment.com/hypnosistreatment.html, which has thirty or so recordings for free. The sound quality is not the highest, but I like the inductions generally.
Other than that, there’s not a lot out there. Some sites, like my Hypnotize Yourself Today site at http://www.hypnotizeyourselftoday.com, offer a free MP3 as a bonus when you sign up for a mailing list. Which is more like a trade, really. And I’ve never seen an MP3 longer than 20 minutes unless it’s for sale.
References :
http://www.freehypnosistreatment.com/hypnosistreatment.html
http://www.dpierce.com/trance/hypnomp3.html
http://nlp-experts.org/nlp-hypnosis/90-hypnosis-mp3-downloads-free.html
http://www.hypnotizeyourselftoday.com