Without knowing which paper and/or city or region you're talking about, it's impossible to estimate. According to my wife, who is a career journalist/editor, freelance fees can run anywhere from $30-$50 (U.S.) per assignment for a small-town paper to thousands for a New York Times travel piece. For the past five years or so, she was the art director/sunday editor for a 100,000-circulation paper in southern New York, where fees usually ran in the neighborhood of $100 per assignment, though they could vary somewhat. Beyond that, I'd be guessing - I haven't accepted freelance assignments (except as an occasional favor to my wife, which I do free of charge) since the early 90's, and once photo editors hear my list of excuses, which can include broken vehicles, broken cameras, broken legs, impending prison terms, mental illness, and/or an inability to communicate in modern languages, they pretty much leave me alone.
Peter J