I've given this subject some thought. I don't see why somebody couldn't build a retreat/retirement center for lay people from the ground up and do it for dirt cheap.
All anyone would really need would be some rural acreage with lax/no building codes, a few thousand dollars and a handful of able bodied volunteers. Basically, just start with a campground and build one central building with community baths and a meditation hall. Then build a few dozen hermitages/homes across the site. You could probably even convert the central building to a monastery if the need arose.
Rather than build expensive conventional western buildings, I think the key here would be find people who were willing to live in alternative structures like those based on Mike Oehler's designs:http://www.undergroundhousing.com/index.html
Those underground structures seem to have many design features that would appeal to Buddhists. Although, I can imagine that some may not want to live in them. Surely, if it was made affordable enough there would be a good number of Buddhists who would want to live in them. Since the costs of building and maintaining these structures are low, they could be rented out for a lot less than conventional buildings.
Such a center would cost a tiny fraction of the one in the link that Tilt posted. And for people that can't even afford that, but want to do some retreats, campgrounds could be made available for free. It doesn't cost much to let people camp on some land. Camping might appeal more to some folks who are interested in doing shorter retreats.
To the point that David brings up. I think such a community would be best suited by maintaining central ownership (in a non-profit organization) and renting out the buildings. I would think one could write up rental agreements that would give the people free reign to do as they pleased with their structures. Also, if the rent was cheap enough, people could pay for years in advance and not have to worry about it.
If I had the land and the money to do something like this I'd probably give it a shot. Anybody want to donate some acreage?