It is not a full version but it is crippled to be 32-bit only, not 64-bit as the professional version is.

Mathematica Home Edition is available in the UK @ £195 - see

http://www.wolfram.co.uk/products/mathematicahomeedition/

But also consider using Sage, which is an open-source program. In some areas (e.g. number theory) it is way ahead of Mathematica. Others it is eqaual and in others (graphs) it does lag Mathematica. But there is a huge development effort on Sage, with funding from Microsoft, Google and various govenment bodies in the US. Sage is impressive, and would appear to have a very bright future.

Note you can't get premier service with the home edition, so I'm not sure if it can be updated without buying a new version. If that is the case, it is not such a bargain as it might first appear.

Wow, two comments in the space of 15 minutes!

Anonymous commenter no. 1: My understanding is that it's a full version in the sense that all the functionality is there. I can imagine that the 32-bit edition would impose some limitations, and as I only uses 64-bit operating systems on my desktop and laptop machines, I would certainly perefer a 64-bit version. But practically speaking, I find it hard to imagine that I would really notice the difference, and I expect that the same is true for most potential users of the home edition. If I'm underestimating the constraints of the 32-bit version, I'd be happy to hear more.

Anonymous commenter no. 2: Thanks for the update; I'm glad to see that this offer is now more widely available. I think you got the URL slightly wrong though (no 's' in products). I'll add an update to the original post with the correct URL in a second.

I'm a heavy user of Python, so I do have some exposure to Sage; I believe some packages that I regularly use are bundled with Sage. But until now I understood it to be more comparable to Matlab than to Mathmatica. Perhaps I have been mistaken, and I should examine it more closely.

But as my post hinted, I don't really have a need for the mathematical capabilities of Mathematica, impressive as they are. It's Mathematica as an interactive computing environment that really grabs my attention. I wonder how Sage compares in those stakes?

You point about the upgrade issue is a good one, and something I would look into if I do think about making a purchase.