what price range does a deacent leathe or milling michine cost
A new Bridgeport will run from $12K - $20K and up depending on options and tooling. Used copies, in decent shape can be had for ~$2K and up, but sometimes you can find a deal. My brother just ran across an old Lagun (knockoff of a Bridgeport) for just a couple hundred dollars. Nothing wrong with a used Bridgeport, Lagun, Sharp or Tree. Decent lathes are kinda the same, price wise.
People can and do make very nice, precise parts by cranking handles, counting turns and approaching from one direction to minimize backlash, but I would highly recommend that you get machines with digital read outs; they'll make your life much easier. Both lathe and mill should have them, but more important on the mill.
Tooling will likely cost more than the machine. You'll need/want stuff like vises, angle plates, indexers, rotary tables, parallels, clamps, collets, chucks, boring heads, face cutters, end mills, drills, taps, boring bars, reamers, carbide inserts.... the list is nearly endless. Then you'll need/want measuring tools... ID, OD and depth micrometers, calipers, test and travel indicators, bore gages.... ad infinitum.
Then you gotta kinda know what you're doing. Machining gun parts should generally be fairly easy and most people could learn. But developing good machining skills is not for everyone. Decent math skills, good spacial perception, patience and practice are required for success.
Not to discourage you and I will say you can piecemeal a lot of the tooling and learn as you go, but I want you to know what's involved here. It's really not just buy lathe, buy mill, fix guns.