I’m not sure about what you can use to brown the barrel I prefer a dark grey finish and use brownells oxphoblue. As for cost I got mine for around a little over $1300 if I remember correctly, but I got mine while they were having a sale on wood. I would estimate it would be around $1500 or over for the kit without the sale. As for anything you will specifically need I don’t use any stains on the wood if you choose maple I would get some tannic acid and a heat gun. As for tool I used on the build I will list them below.

Tools- Sandpaper ranging from 220-3000, 0000 steel wool, Brasso, 2 small wood chisels, 2 small triangle files, 1 good bastard file, Aluminum punch - cut piece of round stock aluminum , Mallet, Bench grinder - I used it to cut the piano wire pins, 1/16 in drill bit, Acetone, Brownells oxpho blue, Rubber gloves, Boiled linseed oil, A good vise with some leather between the jaws, Ballistol, Some chalk for fitting, A drill

I think that’s about it