Yes all the money invested is going to advertising the site, so more ads more traffic. Like i said the price is for life as well.
I wont be able to but a banner because it messes up the design. But i can put a link on the top of the page Like this one: Register Today! ConsultexForum.com Is Giving Free Ipod(s) If you would like to do that?
Also the bottom really gets alot of views such as when you sign up, and make a post. Try to make a post somewhere and you will see what i mean.