dr. bois is right on the money. start simple and inexpensively and grow from there. you can be into this craft for a bunch of money before you know it. i'm surprised he didn't mention using milk containers for stencils...one of his trademark moneysavers... they're the right thickness, usually around every house, and work great. when you getto foring stencils you can easily make your own vacuum box. in fact i probably have the parts to make one around here somewhere that you're welcome to have. just hook it to a shopvac, use a heat gun to soften the plastic and you'rein business.
remember too that less is more. that will make sense as you gain more and more experience. get your paints from walmart. water based acrylic..usually $0.50 a bottle..and more colors than you'll ever need.
a great way to start laying down "patterns" is to use fabric. it' isn't expensive and it can give you some very realistic looks.