News directors at real news outlets want relationships, business partnerships, with known and trusted nightcrawlers. They're also not willing to use low-quality footage just to get the story. There's no fixed rates, and the same type of story can be worth nothing or a lot. It depends on the news director. Any outside force (international news, national news) can displace the need for local events. News is in competition. Nightcrawlers can also get interviews, which increases the value of their story. They sit and listen to 5 or 6 radios, they chase stories, they use high quality longdistance video equipment to get non-shaky footage close in.
In LA, the stories they sell, if they sell, are worth between $100 and $50k.