They used to be free but now work on a bidding system. If you do a search for many common items in G you will see a small cluster of images to the top right side of the PPC results. The title will read, "shop for item on Google" and if you click you get a catalog looking results page with thumbnails of search results from different merchants who participate.
You're not really making sense. What do you mean by "buggy"? I noticed an improvement compared to before (when searching for a product, it sometimes turned out to be a part for it, despite the product listing details).