I don't read poorly-written books; I've just return a half-dozen to my local library that I started but couldn't finish.
Dan Brown's dreadful novel, The Da Vinci Code, is one example. The writing was so poor and the plot so ridiculous that I couldn't finish the book. Now I read that he's about to publish another novel, The Lost Symbol, and that many retailers won't be able to sell the book for much profit and in fact the popularity will work strongly against small, independent book stores.
Sight unseen, however, I'd avoid this book at even 100% discount until you hear from someone you trust that the book is worth reading.