Welshwitch,
You have to have clean sputum culture, as in no b.cepacia or MRSA in the last two years. Or any other bug that is resistant to all antibiotics.
The cost of the CFRI retreat is fairly inexpensive. $65 covers the whole week, meals and snacks included. Plus $40/night accommodations are available onsite at the retreat center. Most people stay there, though you can stay at any hotel in the area, or friends house too. And if the tradition continues there are scholarships available.