Think about blender, open source and a complete package,

UI is daunting at first, but, most computer literate kids will get it pretty quick.

http://www.blender.org/

GIMP for photo editing again open source and it's only real pitfalls are a little bit of an odd ui and no CMYK.

http://www.gimp.org/

cost for both = $0

You might also want to think about Wax (compositing - http://www.debugmode.com/wax/) or jahshaka for vid editing (haven't tried the latter I use adobe premier - but it gets good reports)

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Toolset: Blender, GIMP, Indigo Render, LuxRender, TopMod, Knotplot, Ivy Gen, Plant Studio.