I used a Char-Broil Silver Smoker (~$150) for years. It's a piece of shit, leaky, entry-level offset smoker, but with some adjustments it works just fine.
My adjustments were a few bricks to hold the lid tighter, foil lining everywhere to plug leaks, and some foil to redirect the smoke from the firebox a little more efficiently.
I would suggest starting at the $300 range for an offset smoker, something
like this.
For fuel, I prefer a 50/50 applewood/hickory mix for pork. With 100% hickory I find the flavor can get a little bitter-- and 100% applewood doesn't get enough of that kick from hickory.
Experiment with any kind of hardwoods, particularly fruit and nut. Hell I used cottonwood in a pinch once and made the best butt ever :D.
Great resources at
www.thesmokering.com. Real BBQ geeks ;).