1. The Bluelight/Erowid community has compiled the "Erowid/Bluelight Neuropharmacology Text" right on this site (
link).
2. Search for "Nelson & Cox Lehninger Principles of Biochemistry 5th edition 2008 pdf" on Google and you'll find a number of links for the free comprehensive college-level textbook.
3. Browse
MIT's Open Courseware website for free online courses related to chemistry.
4. Trade a college student some pot for their login information and you can access their University's Library's network from home by proxy.
5. Register for public access to
JStor. They made limited rate of access for the public a possibility after a guy named
Aaron Swartz tragically killed himself after being arrested for illegally downloading journal articles from them. He believed free access to academic knowledge was a human rights issue. They disagreed. It was bad press.
6. Last but, emphatically, not least, learn to use your public library. If you know how to get the most out the public library system you can learn almost anything you can learn in a university and a hell of a lot more. If you're willing to use what you learn to do free work and prove yourself you can even get jobs without a degree. As convenient as the internet is it's actually not that great for learning because (esp. young) people associate it with instant gratification and simply don't seem to be able to read online without bouncing around skimming everything with shallow focus (see"TL;DR").
A persistent autodidact can easily learn endlessly in this day and age.