You could try get some niche market advertising for the niche forums.
The Spirituality forum, could have 1 small advertisment on it,
just a link and a small banner for some holistic spiritual website.
an example would be www.sacred-texts.com
that covers most such spiritual areas.
said website could pay you a small fee.
since you are advertising them to people who actively debate spiritual issues.
Just an idea, not sure if its viable, or practical for your business model.