Welcome to the forums.
Whether you found it by accident, were directed here or whatever, we're just glad you found it.
Sci-Fi pin-ups, eh? Those are cool. John Eaves does some cool Star Trek ones that he posts on his blog.
As for being on a budget, join the club. Most of us are.
I use a much free and open source software as I can. BTW, if you like what ZBrush can do, check out Sculptris:
http://www.pixologic.com/sculptris/ All you have to do is fill out a simple (free) registration form to download the software. I've been told that it's similar to ZBrush, though I've never used ZBrush, so I don't know for certain.
