Mathematica is super expensive for personal use, unfortunately. Good if you're really into it, but hard as an impulse buy (plus they discriminate based on country and double the price in some places).
I use the Home Edition which I bought for just under $300 a while back.
It is a great mathematics playground, although, concerns over being able to peer review the engine or calcs in the software are valid, not for what I use it for.
It is like Emacs for me. I leave it open all day, and just play around in it. The multiple programming paradigms are fun too for coding practice.
It's showing me a price of $310 for the personal edition right now. I think that's worth it if you're going to get a couple hour's usage a month out of it.
