It depends, anything is available if you're paying the right price. But usually pricing is based on the site's demographics, the site's subject matter/prestige, how intrusive/prominent the ad is, etc.
While the average joe might get a $2-10 cpm (cost per 1000 views) from adsense if they're lucky, prestigious sites can make cpm's upwards of $70-90 by direct selling their advertising to brand marketers. If your site is frequented by the right people (read: politicians), you can make cpm's upwards of $364 (!).
Here are some example prices from 2009:
- AOL homepage takeover: $500, 000 to $700, 000
- Yahoo! homepage single day roadblock ad: $600, 000
- Turner Networks all-site day long roadblocks: $500, 000
- YouTube homepage single day roadblock ad: $400, 000
- Kim Kardashian’s tweet stream ad: $10, 000 each
- National Journal Energy Blog: $364 CPM
- Wall Street Journal video: $75-$100 CPM
- Economist.com: $91 CPM/site takeover
- Forbes.com per welcome interstital: $90 CPM
- CBS March Madness on demand: $70 CPM
- Daily Candy daily e-mail: $70 CPM
- WebMD: $40-$60 CPM
- Bloomberg C-level display inventory: $50
- ABC.com full episode player: $45 CPM
- Hulu: $35 CPM
- Martha Stewart Living: $25 CPM
- ESPN Brandchannel, YouTube: $22 CPM
If you want, you can also email their ad department and ask for pricing on some of their advertising slots. It shouldn't be too hard.