You don't have to pay for a book reviewer. In fact - okay, my opinion here - as an author, you shouldn't pay for a book review.
So how do you find someone who'll review your book for free?
You check out who's reviewing other peoples' books, you go online and search, you keep your eyes open ...
I share my thoughts on this subject in my blog today at http://www.plblairportals.com (Just click above the photo of my gorgeous basset hound and me).