Call or stop by Mission Moulding on Chesapeake. They have all the materials one would need for the actual banister and may have some way of helping estimate the costs.
I’d guess the milled wood for a nice banister is gonna cost a couple thousand dollars, and a carpenter may want several thousand (3K+ ?) to put up the new railing and finish it, but you have to take out that wall first and, as mentioned earlier, the big cost uncertainty lies in the purpose and structrue of the wall that is being torn out.
If the wall is “easy” to prep (no plumbing, electrical, or ducts, a framer and drywall guy could run another couple thousand. I’d guess $8K on the low end and up to 20K on the high end.
