Weird supplements

My doctor suggested I look for capsules of an extract of the mushroom Coriolus Versicolor while I'm travelling in Canada and the USA. Its not available in Australia yet, and the research for its immune system boosting properties look good. If I buy it here, I can save US$20 on shipping. So far, I can find it online at every price from US$20 to $60, and its hard to work out in the unregulated health food industry which product contains the PSK and PSP polysaccharides I want the supplement to contain. While google-surfing for a deal less than $60 that appears to be a genuine product, I found a Venus Flytrap extract being sold as an immune boosting product "Carnivora". This amuses me, I have grown venus flytraps and other carnivorous plants since I was 15. As a grower of venus flytraps, I can tell you that its supposed to be a flower emerging from the top of the plant, not non-functional leaves as they appear. Hopefully Coriolus Versicolor as sold here in North America will approximate the Krestin sold as a pharmaceutical in Japan, and mean that I don't catch every cough or sneeze borne virus I come into contact with.