does anyone know cost of msn advertising/messenger

[biznatch]

does anyone know what it cost to have a banner in rotation on the bottom of your "contact list" for msn messenger? (when you sign in and you go to your list of peeps) or even where to look, i cant find advertising costs or quotes anywhere, or if you know of other I.M. advertising costs, Aol, icq, yahoo, skype, ect ect

any positive feedback would be great, many thanks in advance

B.