J.K. Rowling wrote Harry Potter while a single mother on welfare

Between 1990 and 1995, J.K. Rowling conceived Harry Potter on a delayed train, lost her mother, moved to Portugal, married and divorced, gave birth to a daughter, and moved to Edinburgh where she survived on state benefits. She wrote in cafés while her daughter slept, unable to afford a typewriter. The manuscript was rejected by twelve publishers before Bloomsbury offered a £2,500 advance in 1996. Within ten years, Harry Potter had sold 300 million copies. Rowling has said she considers the failure period formative: 'You might never fail on the scale I did. But it is impossible to live without failing at something, unless you live so cautiously that you might as well not have lived at all.'

Source: Rowling, Harvard Commencement Address (2008)