Can I offer free advertising in the “Advertising Marketplace”?

I have a site that offers free banner advertising slots. All advertisers need to do is let me know the link to their banner and the link they would like it to point to and I will give them a free banner ad on the site.
Can I promote that offer in Buy, Sell or Trade > Advertising?
If not, is there another section on DP where I can post this offer?
Thanks!

See original post by Fergal