A monastery of nuns or monks is something like that: https://en.wikipedia.org/wiki/Enclosed_religious_orders
Even though the members live a minimal lifestyle of near-poverty, many monasteries are still not truly financially self-sufficient because their funding comes from an associated church's donations.
Amish communities may be an example of lower-cost living while being financially self-sufficient via selling crafts and furniture. (They're even financially independent enough to be exempt from paying and receiving government Social Security money.) It would be interesting to know of other communities that deliberately replicated Amish living (for cost/benefits) without being Amish.