Most people on the internet today simply ignore most banner ads and move on the other things. Also the costs far outweigh the effects of banner ads. If you are really going to spend some money on an advertising campaign stick to a good e-mail campaign and text links.

Text links are shown to get three to four times that click through rates of banners. If you are going to go ahead and use banner ads, make them look professional as possible. If youa re going to do a large banner ad campaign, consult with a professional web designer and let them make the banners for you instead of doing them yourself. You'll see much better results from your campaign.

I would also advise against using banner exchanges. While they seem like a good idea on the surface, it's tough to know what banners are going to be shown on your site. Remember, everything on your site reflects your business. Do you really want to not have control of what shows up on the front page of your site? Avoid these services, the traffic you get from them will be minimal and untargeted anyway.