I hope I'm posting this in the right area. I am negotiating a small banner ad on another site highly relevant to my own. They claim to get 80,000 visitors a month. They rank #3 for a search term that returns about 2 million results. My usual ranking for that term is #11 - #16, but this month Google has screwed up and moved me to #55. This is a critical month for my web business, I am trying to take some measures to moderate Google's error.
What is a reasonable amount for me to pay for a very small banner on the other site's page? (Ad is about 1.5 inches wide and 2 inches tall)