We call it kbsearch. Here's the direct link: http://www.kindleboards.com/search
Most people use the search tool this way:
- Go to http://www.kindleboards.com/search.
- Set the maximum price to "free" using the pull-down option.
- Choose to include, or exclude, public domain books
- Pick a sort (by price, by bestsellers, by ratings, etc.)
- Click the search button!
Also, on the right side of the screen we have a list of common searches. Just click on a quick-link there and an Amazon page will appear with the results of that search.
Have you tried kbsearch? Give it a try at this link!