This is a tough question to answer due to the number of variables involved with publishing one’s work. Not all writers submit to the same type of publication. Some hope for a published novel, while others write short stories, articles, instructional or how to type pieces, and so on and so forth.
One must consider what type of writing, such as genre, and even length of publication. Some pieces of writing pay per word, for instance. Is this is a short story or non-fiction article? Do you publish a book, or a series of short stories?
Some publications pay per word such as $.05 per word. A 500 page article could sell for $25 or a 1,000 word story for $50. Novels, on the hand, can earn a writer $5,000-$10,000, not counting royalties or if the book gets on the bestseller’s list. This depends on the agent and publishing company, the quality of writing, the amount of writing and re-writing needed, and if the books sells well.
The one thing I find in researching earnings for writers is that a novelist writer needs to CONTINUE WRITING after they publish their first book. Don’t think you’ll hit it big with your one big idea; you’ll need more ideas, more stories, and keep publishing books to make a living as an author of novels.
Other writers include freelance, who sell articles, short stories, and content pieces to the market. Reselling and reprinting their work earns them even more, providing they find the outlets for their work.
Finish whatever novel you’re working on. Don’t let fear of rejection or failure stop you.