All of our services are free of charge by default. We don't even have usual ads on our own website.
At the minimum you'll only need to use our game advertisement banner on your game -- which only advertises other free to play games. We are always open in hearing your business proposal. We assess every request for service individually and reserve our right to reject our services for any reason.
You are free to have your own ads on your games. However we might reject our services if your game has too many of them.