I buy reloading supplies from Gene Sears and Powder Valley. I use Alliant powder but Fio primers. I haven't bought factory loads in a year or so, but I bought them from Cabela's and Walmart because of a big sale or clearance I ran on to.
Virtually anything else I buy (non-firearms related) is, as Gold E succinctly stated, purchased at Big Box retailers (never Target, though).
I would love to say I buy only US-made products, but there is so little made in the US nowadays. I shoot a Ljutic, but I have Italian and Jap shotguns as well. All my rifles and all but one handgun (Croatia) was made in the US except for the Belgian made action (FN) of a custom wildcat. All my vehicles are US made. How much foreign parts are in them I know not.
You do what you can, but choices are limited.
Old Marine