Yeah, its $125 for Armory Kote, $175 for the Black T (which comes in green, supposed to wear longer and have some self-lubricating properties). Shipping excluded.
I've tried a couple different spray-and-bake finishes, though none of the factory offerings (a little expensive just for testing). The GunKote is difficult to scratch, and once scratched doesn't chip. Its a very thin coating, and resistant to every chemical cleaner I've thrown at it.
The GunKote is $30 (shipping included) and an airbrush at Walmart is around $20. With the parkerized parts, you should be able to apply the finish over the rough parkerizing with great results. With stainless, you might need to sandblast any smooth areas to rough them up. Sandblaster is $13 at Walmart and aluminum oxide media is pretty cheap (Got 22lbs from Harbor Frieght for $10? and used less than a pound of it sandblasting the frame twice). You can use a cardboard box for a cabinet. Of course, you'll need an air compressor.
IMO, the nicest thing about the GunKote route is that when (not if) you scratch the finish, touching it up is a simple matter.
Jonathan