Truly affordable cohousing and accessibility are the current hot topics on the Cohousing mailing list. Although there is a concerted effort at many projects to have some units available to people with low incomes, posters (including myself) have suggested that many new building techniques can open the cohousing threshold to low-income and poverty-level people.
Most projects have an entry-level expense of about $200,000 to $300,000 and up. A typical three-bedroom home in cohousing can be the same price as comparable homes in that geographical market. Project home prices often are slightly higher than comparable homes when the shared expense of developing the community (Common House) and/or 'green' construction features are included.
Affordable housing examples that could cost anywhere from $20,000 to $100,000 include smaller houses (less than 1,000 square feet), prefabricated or modular homes, converted shipping crates, Katrina Cottages, or homes built entirely of recycled materials. Many of these types of dwellings are discussed on the Small Home Society mailing list and on a growing variety of web sites focused on sustainable and ecological building construction.
I'm looking forward to further discussions and will include new information here as the topic unfolds. Please contribute your observations or opinions about truly affordable cohousing in 'comments' to this post.