This extension is the only one I could find that meets my client's two biggest requirements - it can show in the main page instead of a popup (unless you want a popup) and it can have ads placed on it.

It installed no problem and when I ran into a small glitch because of another extension on my site, Peter answered my email within minutes and did what it took to get me setup... And on a Free account, at that.

Both the support and the extension are great and they are striving to make it even better.