i have never run into any issues with mixed brass (.38 Special and .45 Colt.)
That being said, my only experience has been plinking-type ammo, though they are semi-wadcutters. Relatively low numbers to boot.
I use a Lee Classic Turret Press.
If über accurate match loads were the goal, might be more persnickety.
Straight-walled pistol (or revolver for you purists) cartridges are somewhat more forgiving for this sort of thing, at least the way I understand it.
As for the nickel plated, don't recall if I have loaded those up or not. As I recall, common advice states that until the plating begins to peel, you should be alright.
Again, just personal limited experience.
Wiser heads may expound upon my statements.
In regards to price, can't say. What I have loaded have started out as factory until I emptied 'em. Excepting some reloads what came with my used Rossi '92 (.45 Colt, believe it was Starline if memory serves.)
Be safe and enjoy.