"keep in mind that silicon wafers are still quite expensive and probably too expensive for human scale objects"
That is wrong. The expensive part in silicon chip production is the process. It's just that hard to make working circuitry close to the molecular scale and a lot of sophisticated technology had to be developed for it (i.e. a lot of R&D invested money), hence the high cost of production nowadays. Here however, it's about close to no fabrication process (by comparison) and the purity of the raw material involved will not matter that much either.