When I first got my Kindle, I went overboard on the freebies, and most of them were just so-so, not well written, and so on. And there were so many I couldn't keep up! I've pretty much stopped doing that, and will buy books by certain authors I like, full price or not, but I also check out some of the websites that list "deals" Amazon and B&N seem to price match, so many times the same books available cheap on one, are also on the other. every now and then too I find a steal by a best-selling author. for example, i really like Kathy Reichs Temperance Brennan books, and recently scored one I hadn't read for 2.99.
i also read reviews if something looks interesting, and if the majority of them are good, I will take a chance. But the downside to all of that is I have tons and tons of books waiting to be read! I don't feel quite as disappointed if I only spend a few dollars and it turns out to be stinky.
the one that really disappointed me was by the author of the blog "The Bloggess"I think i paid 12.99 for her book, and quite honestly, it was terrible. Her blog is funny, but the book was not.