If you have to buy brass, check out GI Brass Sales, located in Lanesville, IN. Good people and good prices, even better if you can pick up and save on shipping.
NOTE: I am not associated/related or gain anything from any sales.
Most dealers at gun shows won't pay squat,when I get too much of something I take it to Kroots scrap metals in Columbus,the pay twice as much as any scrap yard in Indy.