Here in Pennsylvania I acquired most of my 4500 once fired 30wcf (30-30) cases in one weekend, by driving around to several (three) state ranges the weekend before opening Day of deer season (an unofficial State Holiday) when Everyone and their Uncle and all their cousins were sighting in their deer rifles.
Back then I also collected a couple of hundred 32Win Specials, but Some other guy was collecting those and he offered me all the 30-30s he had collected for them (I traded).
Some other guy was interested in the 50 or so 38-55s he had collected and offered me half a 5gal pail of once fired R-P 30-06 cases and I took that deal as well. it offends me when I find a guy collecting reloadable center-fire brass for scrap, and I'm always happy to trade something I don't use for something I will, but Range pickups are easy to get particularly just before deer season opens and even scrappers are not immune to the song sung by pictures of Dead presidents (Jackson and Grant) and founding fathers (Franklin & Hamilton)
Just remember New Virgin brass is $80 for a hundred in most popular Rifle cartridges, stuff that isn't popular is often priced so you'll ask is it made of silver? Like one of my Brother's Rifles he has a 30-378Weatherby and those cases might as well be made of silver at $4 EACH