A friend of mine bought the Calvert spirit cabinet from Hocus Pocus. What you get is a video that shows a performance and how Calvert's rope tie works, the cabinet itself and a bunch of props (tambourine, bucket, ropes, etc.), and two audio tapes of the music Calvert uses.
The cabinet itself is very well-made, and it's probably worth buying just for that. With the rest of the props, you have all you need to start working on the routine. (You need to provide chairs for yourself and the volunteer who later sits in the cabinet with you.)
The routine is advertised as a "one-man" spirit cabinet, in that you could do the whole thing yourself and cue audience members to raise and lower the cabinet/curtain. I don't think this will be as effective as having your own assistants who've been rehearsed. John's rope tie will allow you to go into the cabinet, get tied up, and cause the usual ruckus all by yourself. It's a simple, effective method.
One thing...the two audio tapes with the music are awful. I think John picked some music 30 years ago, kept it on reel-to-reel tape, and then copied that onto the cassettes. Not only is the music dated, but the quality is very poor. However, this is the easiest part of the whole thing to fix, there are so many options for getting music these days and playing it back.