Most of the audio we produce we give away for free in iTunes (or through our email lists), but we charge something for the eBooks (containing transcriptions) that go with it. This supports the running costs of the websites, and allows us to develop more materials.
All of our eBooks are available as part of our downloadable packs in the shop at https://zappenglish.com/secure/shop.
By distributing the audio free, we hope that everyone benefits, but those people who are really serious about developing their English further have the option to invest in the accompanying eBooks too.