Free trial for 30 days, but I'd suggest searching for some video tutorials, watch them a couple times, then d/l and start properly, it helps to be vaguely familiar with it before you try and do something as big as animating.
It's pretty easy to just move stuff, and even get all the key points right, but to make it look good is a whole other kettle of fish.
Try Clan of teh Dead Goat for lots of tutorials, you'll need to go to their forums, though.
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