Yes, following the diet can be expensive as you point out. However, if you make most of the cultured foods yourself (obtaining starter cultures on the Internet) and buy conventional produce rather than organic (making sure to scrub it with a produce wash before consuming), and canned fish rather than fresh... it's possible.
But as I said in the other post, I don't feel entirely comfortable discussing the particulars of other approaches here because this in a BB for Heather's approach - which I want to honor and respect.