Free: one big box of assorted stars from Goodreads
For the record, I'm now in the midst of stripping the star ratings off the books I've reviewed on Goodreads. I'm going to try out a review-only, no-star-level method. I feel too much importance is placed on the number of stars rather than the words. If someone writes a respectful review saying, "I liked A, B, and C and thought the flaws were X, Y, and Z," and posts that review under a two-star rating, the author will likely be hurt or angry. But the *exact same review* under a four-star rating will make their day. Subjectivity is too much of an issue, to make a long problem short.
So if I've reviewed one of your books, don't worry, I still like it, and the review will still be there. Just not the star rating. And it'll take me a while to work through them all.
Amazon, unfortunately, forces you to pick a star rating (that is, I haven't found a way around it yet), so I'll have to decide how to handle things over there. Hm.