Online site BubbleCow provides writing advice, tips, and professional copyediting services. As an end-of-year thank you to their readers, they're offering free advertising on their site for any book, indie or otherwise.
The ad is strictly text, so there's not much work for anyone who wants to take advantage of this. Just add the text you want displayed along with a web address where people can learn more about your book, and you're done.
The ad itself is a single-line dropdown at the top of their site which will appear on each page visited for 1 day. They're taking as many books as people want to list and will run the ads until no more books remain.
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