spray painting my uni

i really want to do a paint job on my new uni coming in the mail with green and orange. but i have been reading around on the forum and some people talk about powder paint or something of that nature.
what is it?
and would it be a bad idea to just go to the hard ware store and buy a couple of cans of spray paint and just paint it that way
also would i need primer or something to go over the top of the paint when its done?

I guess a spray paint your uni faq would be nice or what ever advice/answers you can give would be cool