Do you know what version of Dragon is being sold for $79? This seems like an insanely low price for Dragon Professional and too high of a price for Dragon Standard. I paid less than $30 on a one-day promo for Dragon 10 Home from Amazon.com. Amazon really is the best place (and I've done a bit of research) to buy this software. If you buy directly from Amazon, you should be able to get free shipping and avoid paying state sales tax, unless you live in Washington State.
Be wary of paying too much money for Dragon 10 because version 11 is already on the market. If you're looking for opinions on the usefulness of Dragon, several threads have already been posted on AW, with really detailed and helpful opinions offered.
My take?
There's nothing instant or seamless about Dragon Naturally Speaking. You have to put in at least a few hours (I recommend at least eight hours) training the program to recognize your speech patterns correctly. I have Dragon 10 Home version, and several people told me I should have bought Dragon Professional, which is more expensive. What frustrates me is the randomness. One day Dragon will work just fine and another day it won't work right at all. Same computer. Same microphone. To be fair, my situation is likely one most software users won't have to deal with - I'm almost completely deaf, and I probably shouldn't even be torturing Dragon Naturally Speaking with my voice.
I had absolutely no luck with wireless microphones or standalone plug-in mics, but what works beautifully for me with Dragon is a cheapie $5 clip-on mike (it plugs into the headset jack on my PC) I bought from an Ebay seller. I have torn through cheap, mid-priced and expensive headsets and microphones of all kinds, and I've abandoned all of them, except for my cheap $5 clip-on microphones.