This is a 5' tower I recently built. Actually built two of them. Cost about $175-$200/ea to build, but my dad owns a metal shop so that is his pricing. This one isnt painted, but will be. I already painted the other one. More time is involved than you think. So if you're thinking $850-$1k/ea is high, like i did, its NOT.
Edit: forgot to add this tower is for a 4x6 blind w/ a 2' landing. My 4x6 stands have the door in the 4' side.