No, our service is completly free. We do however use some of the banner credits that are generated. This means that you must display 2 banners on your site to have your banner displayed on another site. This type of ratio is very normal for banner exchanges. For one very simple reason, targeting.
Most banner exchanges have almost no targeting.
This means that your science fiction banner is as likely to appear on pets sites, linux help sites, mp3 sites as on a science fiction site. This is bad because people surfing a pet site are less likely to be interested in your site than someone surfing a different science fiction site. This is only possible because we have such targeting. Ok, I am convinced. Add the html code provided to your website and upload your banner to the exchange.