I just made mine (SUPER CHEAP) out of four pieces of coroplast. (AKA corrugated plastic). All the sign shops around me wanted $100-$200 a sheet so I went hunting elsewhere. I found it was much easier finding a place that had it when I referred to it as corrugated plastic. I got mine from a local hobby shop and it's made by Elmer's. You know, the glue guys. Call around and if they don't know what you are talking about, say it's like cardboard or foam board, but plastic. That helped me. I bought four 20"x 30" pieces in black. After I trimmed I used black matte duct tape to tape the pieces together and then scored the plastic. Make sure you find matching duct tape so that it doesn't look icky. Black-on-black looks awesome with black cubes and black cable ties.
Total time to make: 45 minutes.
Cost: About $5.00 a sheet @ 4 sheets = $20.00
I got my cubes for free but right now at Target they are 12.99.
Duct tape about $5.00
For less than $40.00 you can have an awesome cage
It's hard to find any cage under that price.
For bedding, I use "Woody Pet." Call your local ag shops and farm supply shops. I think it's a 40 pound bag for $4.95. You don't use much because it expands as the pig pees. Once a day I use a plastic spoon to scoop poops and afterward stir the bedding (so the wet spots are evenly distributed). You rarely have to change the bedding because Woody Pet is soooo absorbent.
Good luck!