A student asked me last week about quoting a song lyric in a piece they were writing. Because they were only quoting one line, and were attributing it to the song and the composer, that was all right, wasn’t it?
No. The safest thing is not to quote a song lyric at all. Even if it’s only one line. To avoid breaching someone’s copyright, you should seek written permission from the copyright holder to use their words in your work. When permission is granted, you should then attribute that quote correctly to the copyright holder. (Authors often use the acknowledgments section of their book to formally thank those copyright holders who have given their permission for their work to be quoted in their text.)
Whilst the law allows you to quote someone’s work without permission, it does so on the condition that you attribute those words to the person who owns the copyright, the amount you quote is deemed as reasonable, and you are quoting for review purposes. Of course, the law doesn’t actually stipulate how much is reasonable, which is where the lawyers come in!
So, if you’re not quoting for review purposes, then you must seek permission (and this student wasn’t reviewing the song). It is the copyright holder’s choice how much they charge for quoting their work. Some charge a fee, others are happy to waive a fee and simply ask for an acknowledgement. That’s up to them. However, many music copyright holders charge a fee - and rightly so - you are using their creation. (It's no different to writers charging a fee to magazines and book publishers for publishing their words.)
These fees can be substantial. In my book, The Positively Productive Writer, I wanted to quote the chorus from a song, but after making enquiries I realised the cost for this could be prohibitive. Instead, I found a different way of explaining the point I wanted to make. Thinking the cost might have been a touch unreasonable, I did a quick search on the Internet and discovered that, actually, the cost was similar to what other writers were being charged.
Blake Morrison wrote an excellent article about this in The Guardian about how he found out, to his cost, how expensive quoting lyrics could be. I recommend reading it. It could save you a fortune. http://www.guardian.co.uk/books/2010/may/01/blake-morrison-lyrics-copyright
So, if you absolutely must quote a particular song lyric in your work, get permission and then get out your chequebook. Because if you don’t get permission, the legal consequences could mean that bailing out Greece would be cheaper.