Hi there -
Following two small self-educational / art projects here using Wolfram Mathematica (see through bushes! funkify your portrait!), a Wolfram representative wrote me to let our readers know that you can get a fully-featured license to Mathematica 7 Home Edition for just $295.
This is a good deal. You can learn more about it here.
By the way, we use Mathematica 7 (I defy you to click that link) at Actuality, and have noticed some great enhancements over v6.
For example, it now runs wonderfully on my 2004-vintage IBM ThinkPad T41 - whereas, in the past, 3-D visualization would close the program. It seems to take advantage of multi-core processors. Also, it comes with new image processing functionality that makes it easier to... aw, heck, check it out for yourself. If you use the professional edition at work, I think it comes with a home-use license too.