In it’s quest to continually make the bidding process more transparent, Google is rolling out a new tool – Bid Simulator.
Look for a little icon 
next to the keywords in your account & give it a click (you’ll only see it for keywords that have a decent amount of traffic & clicks)
Now you see what will happen if you change your bids & get a feel for exactly how different the traffic levels will be if you bid more or less.
It works by looking at your Quality Score (QS), the QS & bids of your competitors (which you of course can’t see) & the probability of your ad getting clicked when in various positions on the page.
You’ll find some graphs are very flat, but others are skewed dramatically – those skewed curves offer plenty of potential to change your bids (often quite a bit) without huge affects on your traffic levels.
Have a play – don’t worry, you can’t break it!
