I got mine from Fullthrottle, bought it off e-bay from them as they were only 224.99 + free shipping I believe, currently they list them for $249.99 + shipping
I got mine right here in the for sale section. It was used and in great condition. No directions but I bug 87geein for advice on the numbers! If you are patient one might come up for $200 or so.
I am also A newbe. I just bought an 86 GN that has a ScanMaster installed but I want to know where I can get the manual for it. If there is a website I can download it from. TIA