I made this animation with The Gimp which is arguably the best end-user free software there is. At least I'll argue that. Best thing about it: It isn't Photoshop. Photoshop is as bloated, buggy, and confusing as it is possible for for a software application to be. Not to mention, expensive. I used to install cracks of Photoshop on some of my computers, but it brings any normal computer right to its fucking knees, then kicks it in the face. Cracks of commersh softer are buggy too, but if you look around on forums, people who pay nearly $1K for a legit copy, or nearly $400 for an upgrade, are having plenty of problems with the 'legitimate version'
Downsides of Gimp: It isn't Photoshop. You may need to figure out where stuff is at, there isn't a huge aftermarket of swank plugins, etc.
But I guarantee you -- it won't screw up you computer. For as little as I use in-computer text editing, Open Office is pretty OK too. If you aren't a hardcore graphics or word processing hacker, there's just no reason to pay (or bootleg) those two programs.
And I actually bought a copy of Paintshop Pro, which isn't horrible, but no longer bother to install it anywhere.