RE: Digging a pit...
Yeah, steel isn't cheap, the prices of a steel pit vary depending on how you want them setup. They used to run around $100 per foot width, but may be up to $115-125 now. So a pit 16' wide would run$1600-2000. But, they will hold up, can be relocated if they are in the wrong spot, and are fairly water-tight if welded properly. As for rust, untreated steel takes quite a while to show any real damage from rust, buta good primer coat will delay that even further. We hunted 13 seasons out of the last un-primed blind we bought before we had seal up some rusty spots with additional sheet metal. I would rather personally spend the money to get a good solid steel pit that I know will hold up for many seasons.
We hadelectric lights, andgas heat run along with a sub-floor with a bilge pump installed under it to keep water out. Very comfortable way to hunt.