Antique shops
Lodge brand is made here in TN. They're reasonable. The Griswalds at the antique stores are outrageously priced. I have plenty of various makes. One of the local antique stores has tons (literally) of cast iron--most of it is affordable, especially considering that you can't wear it out.
If you ever screw up the finish, scotch brite, sandpaper, grind, steel wool--use anything to smooth it back out and reseason it.
Unlike those silly plated finishes, cast iron wears like--you guessed it-- iron.
I have one of those 20+ inchers, don't know what # it is. My grandfather fried fish in it. I haven't used it yet.
Don't let high-acid (tomato sauces) or salty foods sit in the skillet, they're hard on the finish.
Only clean with hot water. NO DISHWASHERS! I see folks do that all the time, how foolhardy. And any cooking oil will season the skillet. Lard isn't a necessity.