I've been researching Right Media Exchange and DoubleClick Advertising Exchange with the intention of running some banner ads on my price comparison website.

Can anyone tell me how Right Media or Double Click make money from their ad exchange networks? I assume they are taking a percentage of sales? How big is their cut? They don't mention how much they charge on their websites.

I'm very new to banner advertising. I run adsense, but I've never done anything with banners. Well, not exactly true, I did write banner management code for the Right Media API back when I had a day job, which is the only reason I know that it exists.