Today I discovered Unpaywall. It gives fast, free, legal access to many research articles that are behind a paywall. A clever and, again, legal idea that truly helps us with our research. FAQ
If you arrive at a journal website and can't read the article without paying, Unpaywall will search for a copy of that same article that is on a legal university research repository or the author's home page, PubMedCentral, etc. In about half the cases, a free copy of the article can be found.