Well I'm sure you can find it online. Not that I recommend it. It's about $100 and version 8 is due out any time, if not already.
I wish I'd known, at Borders not long ago I noticed a UK PC magazine was giving away version 5, which was the first of their really good versions. I've had 4, 5, 6 and 7 and love them. Not sure about upgrading to 8 yet. I might have hit my limit.