Selling ebooks is not the only way to earn money from a book. Authors can also take part in subscription services or give away books for free to upsell other products. But there's also a third option: ads/sponsorships. Two years ago, Digital Book World posted the results of a survey of 5,000 people that found book buyers said they preferred to read a book for free with … [Read more...] about Indie Authors: Earning Money Through Ads/Sponsorships