Umm..who is the head of the Illuminati now?

I concur with Chris on all points, but would like to add that a private tutor can be useful if you have other stuff to do as they fit around your schedule. And a smart phone with good dictionaries installed as a study aid (enabling you to look up characters and write them on screen for instant recognition), plus enabling you to record or download and replay chinese lessons and vocab anywhere.

Learning anything is dependent upon how far you want to go. So people just want to have survival skills. Some want to write books and give discourses. All the point Cris8080 pointed out are good. If you want to learn survival Chinese then having a tutor could be the cheaper way. If you need a visa then going to a school is the way.