I operate a web hosting resource site that receives roughly 1,400 visitors per day.
Check here for ad rates, contact me with any questions. http://www.webhostgear.com/4.html
banners are not really the way to go if you want to get top of the search engines. Go with text based adverts thast google loves. so if you want to rank high place and advert: "Cheap Hosting" and this would be going to a link to your homepage. Make sure that the site has a high page rank throughout the site and has lots of pages for your link to go on.