Yeah, I would definitely need to know the number of UV's, the countries of origin of the traffic, and a lot of other marketing and demographic metrics before I'd be able to come up with a reasonable price. Pitchfork is pulling in 250,000 visitors a day and ~1.5M UV's per month and it's one of the most popular, if not the most popular, legal music websites on the Internet. When I've worked with them in the past they charged around $800/month for a small banner. I imagine this price has increased a bit since I worked with them, but that should be a good baseline to work down from.