[creativemedia]

Google adsense is where you pay per customer click. You need to signup in your google account. You set the amount limit you want to pay per day. You create the small ad and it appears on google's first page or within other people's websites that offer google ads. You will pay google every time someone clicks on the ad so even if they do not purchase from you, but they click, you are charged.

Personally, I do not use it. But you have to determine whether or not its right for your business and see what the investment vs. return is on placing the ad.