So earlier this week I used a $100 dollar voucher for adwords and chose a small set of keywords (30). After 6 hours of running, I had already used up $65 worth and I had only received 27 clicks. I had selected the option to allow the bidding to go up if need be (big mistake!). I was disappointed with the extremely low amount of clicks. So today I used a $50 voucher with Microsoft Advertising. I set the max ppc at .45 cents. A few moments after the ad began, my site got a flood of traffic, I set my max money to be used at $80. Over a 6 hr period, I received over 630 clicks at an average cost of .15 cents a click!! I used the same keywords as adwords. What was the difference? I don't think I will waste any money with Google.