Originally posted by Josh
What is the genre of your site?
You might want to build a media kit for advertisers to look through to get all the info about your site and get advertising options and prices. If your site is a very general audience, then you'd want to charge less, because the advertiser won't have as good of a chance of getting sales.
But if you have very direct targeted audience, then you could charge 3-10$ CPM.
Also, placement is key. Advertisers won't pay for a banner at the very bottom of a page crammed with a bunch of other banners.
JMHO...