Most successful internet marketers own more than one site, in fact most own many. My own portfolio runs to a couple of hundred sites, most of them are actually mini-sites. The great thing about mini-sites is they are really cheap, easy and quick to produce, and they allow you to check out ideas - if one of your mini sites is successful then it can be expanded.
Self Made Minds have a great post on mini sites detailing how they can be made and hosted, and how much money you can expect to make from them. Unusually for affiliate marketers these guys have provided actual figures for one of their sites so you can see the real deal!
