It depends very much on local availability of materials, how much prep and transport those materials need, quality of finish work expected, involvement of local volunteer crew, how weathertight it needs to be, local zoning and code and contractor licensing requirements. A "respite space" can be $30k or $200k or it can be a few thousand dollars in sculptural fun refining an existing space and getting you and your friends started on your own creative process that involves dumpster diving and digging your own clay and ongoing weekend mud parties and ends with a bunch of deeper relationships and a very special space that would have ben insanely expensive to contract out and would not have the same soul. Drop me an email if you want to talk about it more.
info@unclemud.com