Ok - I am much less confused now
http://www.freesponsorstuff.com/ has been doing this for a year or so & I do use a lot of their stuff. They call them "Shared Free Sites" & "Shared Galleries" Only differance is that there's 2 ads per page on theirs, one for you & one for them.
I don't mean to sound rude, but I'd have to hold off on using anyone else's until a trust was established.