Have you ever bought banner impressions?

Hey everyone, i am looking to advertise talkfreelance.com next week. I already have several sites lined up for large campaigns, i was wondering if anyone has ever advertised their website through banner impressions?

Has anyone had any GOOD click through rates doing so?

I once advertised banners2go on w3reports.com and recieved no customers at all...the worrying thing was i had 150,000 impressions! Lucky they were free