It's also available for free on your favorite bittorrent tracker or eMule. I'd use a Bugatti Veyron to get my groceries if I could acquire one for free without causing any economic loss to anyone. Hell, I'd use a new one every single day.
i bought mine when i was a student, and it cost me a hundred or two bucks. if i had the money -- yes, i would pay for the non-student version. i don't know of a more multiparadigmy language, and it's more or less the most powerful computational environment available in terms of what you can do
unfortunately the language isn't very readable -- not in the semantic sense, but just how it looks. the usage of square brackets for functions (myFun[arg]) is particularly ugly, and absolutely hideous when nested
For Mathematica, I would buy it if it was required in a specific professional context. For what I normally calculate, Google is fine and I use a TI-89 if I need to solve anything symbolic. Mathematica is significantly harder to use than either of those for me.
And instead of a Bugatti Veyron, I'd get two Tesla Roadsters and buy ten more for friends or as company cars for employees.
But if you can afford it, more power to you. Mathematica is like $2k IIRC.