Bowl Cleans, Best place to get Psyllium,Bentonite in bulk? How long on averaage?

Just looking at the Bowl Cleans FAQ, it says take teaspoons of Bentonite and psyllium, for weeks if not months! Where is the best bulk/non-Chinese herbal company to get this stuff, and how much does it take for a 'first timer"? The costs of all this cleansing is getting expensive!