Selling Banner Ads?

I have been approached by a company representing Lacoste. They want me to set a monthly price for banner ads on one of my sites.

My site is not in the fashion niche but is in a niche that fashion minded people may visit.

They are asking me to give them a quote on one or any of several different banner sizes.

My question is: How should I price this? I have never sold banner ad space before and would appreciate some input from you guys.

No advice?

am not expert but i think depending on your site if it good and have good amount of traffic
$100 to $200 per month
might be

What page views you get?