Thank you all for answering. About bookbub -- a writer friend with a well-reviewed novel used it. Although she initially was pleased by the bump in sales it produced (as well as the exposure -- thousands of copies were downloaded), she was less pleased when some 1-star reviews began turning up that clearly were from people who never read it. She says she will not do free promotions for her second book.
I once wasted some money on a Goodreads ad. I did a multi-site promotion for CEL & ANNA (which did not cost me any money) that was reasonably successful. I planned it months in advance; I have names of several sites that help with free promotion.
I have one novel out there, plus a book of stories, plus an imminent second novel -- that is not a lot of content. I am focused on getting more content out there. Is there any better use of our time than that?
An instructive blog on the subject of staying safe out there regarding promotion:
http://networkedblogs.com/PN0qg