This article in Publishers Weekly discusses the pros and cons of paid reviews and it’s a good read if you have written a book and now you want to promote it. When I say “paid reviews,” by the way, I’m talking about pro (and pricey) review services like Kirkus and Blueink, not $5 reviews on Fiverr.

http://www.publishersweekly.com/pw/by-topic/authors/pw-select/article/64718-the-indie-author-s-guide-to-paid-reviews.html