価格比較ツール by価格なび is a Chrome add-on developed by Freegent inc. It allows users to search various shopping and e-commerce sites, including Rakuten, Yahoo Shopping, and Yahoo Auctions, all in one place. With this tool, users can simply select a text string, right-click, and instantly compare prices.

In addition to manual price comparison, there is also a more advanced automatic price comparison extension available. Users can also right-click to compare prices using this feature. The search form for price comparison opens when users click on the icon displayed in the address bar.

This tool is recommended for those who want to check prices beyond the major price comparison sites. It allows users to check the latest prices on Rakuten and Yahoo Auctions, which may not be covered by the major price comparison sites. There are also cases where lower prices can be found compared to major price comparison sites such as Kakaku.com and EC Navi, so it's definitely worth trying.

Overall, 価格比較ツール by価格なび is a useful tool for quickly comparing prices across multiple shopping sites, providing convenience and potentially helping users find the best deals.