"How much do you really "trust" pharmaceutical companies, whose sole mission is to profit at the illness of others?"
You're propagandizing. The correct question is, "How much do I trust the pharmaceutical companies and all relevant regulatory agencies?"
And the answer is... not entirely. That would be stupid. On the other hand, they do in fact conduct drug trials, and so far I have not had a prescription for the mega-profitable drugs, so I'm not overwhelmingly concerned about whether or not they cheated with their antibiotic tests. I haven't needed an antidepressant, cholesterol medication (which I'm unconvinced actually help), or anything else that might actually be a problem. (And at this point I wouldn't touch a weight-loss pill; evidence would suggest at this point that whatever it takes to fool the body into losing weight when it wouldn't otherwise is virtually certain to mess with your heart, which is one of the prime reasons for losing weight in the first place.)
The question is some sort of binary "trust open source or trust the evil commercial interests!". It's actually "do I trust a possibly flawed system that still uses science, or am I so concerned about it that I'm willing to switch over to a system that can't afford to do science at all?" Some science is, all else being equal, better than no science at all.
"But I guarantee you that if a person is suffering from an illness and cannot afford the drugs for treatment, they'll be willing to try any sort of chemistry that may help."
Only if they are in a situation that can't possibly get worse. I support the aggressive deployment of possible cancer remedies in the cases where we can tell somebody has a week to live, for instance, which our government won't do. Very little can go wrong that is worse than doing nothing. But drugs can have arbitrarily bad side effects that only emerge for a small set of people, and throwing more drugs into the mix will only increase that number. And, best of all, while doctors know about the standard drug reactions, they'll know nothing about your home-grown concoction.
Example: http://en.wikipedia.org/wiki/Toxic_epidermal_necrolysis
Installing something on my hard drive is radically, radically different than installing something into me.