The color changing paint can be really expensive or really cheap depending on how you go about it. If you buy the 3 part kit from Krylon or Plasti-kote you'll do pretty well for the 20-30 bucks you spend. the trick is just to take your time, and realize it'll look a little flat till you clearcoat it. Similarly, you need to spray on several coats of the shimmery stuff. I went with two light coats and then a heavier wet coat. my iBook came out amazing.
Of course, if you've stepped up from aerosols and are looking at playing with air sprayed mediums, it gets a little more complex. If you're working with enamels, then House of Kolor will have the Shimirin paints you want. but expect to need a base, a reducer, a hardener and a top coat. and then clearcoat. Its a lot of stuff to work with and it can be a pain, expecially in the cleanup department.
If you want the easy solution with options, the the Auto Air color from Createx (http://www.autoaircolors.com
) are the way to go. They offer 8 different colors that shift, some with a heavy flake, and some with minimal flake. All of them are gorgeous. In order to work with these paints, you need a black or metallic base coat, the actual shimmer coat, and then any decent aerosol or non-aerosol clear coat.
The base will run you about $6, the actual color between $10-$20, and the clearcoat is probably about $5 a can. For about $30-$40, you can do an amazingly professional job. Now, the colors and the bases are usually sold in 4oz bottles, which is way more than enough to paint a computer of iBook/powerbook size. If you wanna do your G5, your display, and a small toaster, you may need more.
Also figure that you WILL need a compressor and a sprayer/airbrush in order to get down with these paints. But, they're water based and ready to spray so mixing and cleanup is easy They also have a minimal VOC content (Volatile Organic Compound) so they arent as hazardous as spraypaint or enamels.
So, there's my two cents. More like a Buck-Fifty actually, but, information IS power.