Overture BidTool

Overture BidTool

While Google won't disclose what each click is worth, you can try indirect methods such as the Overture BidTool to find out the relative cost of different keywords here.

Overture BidTool displays the relative amounts that each Overture advertiser is willing to pay 'per click' for a specific keyword. You can compare maximum bids for different keywords to arrive at an educated guess about the most profitable keywords for your website.

Remember that what Google actually pays you may vary greatly. But you will get closer with practice! ;)

http://uv.bidtool.overture.com/d/search/tools/bidtool/index.jhtml