I was a very shocked when I've read something like "my AdSense earnings dramatically increased when I started to use AdWords" because I couldn't understand how paying for a visitor that may click on your AdSense ads can be profitable... Is there someone that did this before?
Even if you got $2 per click, and you only paid the minimum, which is $.10, you would need at least 1 click from every 20 visitors you get. Unless your site has proven to do better than that, I would not even attempt it. There is better ways of generating tons of free traffic. The free report in my signature should give you some brilliant ideas! I hope this helped!
It's known as arbitrage - google don't like it and periodically try and crack down on it, but people have made a lot of money from it e.g http://www.webpronews.com/insiderreports/2007/05/21/google-hammers-adsense-arbitrage-sites