The cheapest way to get started in rendering would be to use a free program like FSView, and copy+paste the images into Paint.
Of course, there's always old versions of Truespace, which is a rendering/modelling program, around. I've lost the link, but they're free (and legal).
It all depends on what you plan to do with rendering. If you want to do snazzy special effects, truespace won't cut it. You'd need a professional rendering program. I use Lightwave, since I found it to be my favourite. However, if you want to get professional programs, you'll either have to massively expand that two cents in your pocket, or get to be a very illegal person (I say no more).
