The expensive honing guides do have an advantage. If you look at the picture that Matt posted of the Vertitas guide, there's a guide, so you can insert your chisel and the bevel angle is automatically set correctly for you (The right amount of chisel blade is protruding). I think it's worthwhile, it saves time sharpening, and the easier that you make sharpening, the more likely you are to do it.
Some people can sharpen "Free hand", but I really don't recommend it as a beginner.. When I was starting, I tried freehand sharpening, and over time, my angle got progressively worse.. Yes, it's possible to sharpen free hand, and if that's your thing, I'm not going to talk you out of it, but I really recommend getting a good honing guide.