How much does this banner cost?

Hi guys, I would like to know much do you think a sitewide small banner should cost on a site with the following metrics:

PR: 3
PA: 34
DA: 22
TF: 7
CF: 12
Monthly pageviews: 3000

It's a monthly fixed price, so CPC, CPA and CPM are discarded.

Not much more than $10.