Freelance journalists may work on commission (when they are assigned work) or they can sell articles that they have already written. Most journalists work within a specific interest, such as politics, sports, or entertainment, and cover current events or write editorials. Depending on the agreement with their client, the journalist can charge by the hour, by the article, or by the word. In order to ensure timely payment, both the work agreement and the invoice should include a specific date by which the invoice should be paid in full.