I have a facebook fan page with a lot of fans.. What is the advertiser pay the best for facebook traffic?
Once again just like Adwords, Facebook is super competitive and because of this prices are pretty steep. Also, depending on how targeted you get with your demographics your ads will become stale very quickly. This will result in your CTR dropping and thus your CPM or CPC increasing.
I think any respectable ad network will give you good CPM rates, if you have big volumes of quality TIER-1 traffic and it doesn't matter from FB this traffic or not