You might check GunBroker and see what guys are selling brass for now. I usually price stuff out at half of what new commercial brass would cost and let the market bid on it. I've found it's better to sell it in large lots that you can ship in a flat rate USPS box rather than trying to sell it in 100 round lots, since the shipping is high for a small quantity.
I would definitely sell the Match stuff separate from any other commercial cases since the M1A is making a comeback at the National Matches at Camp Perry and guys will be looking for military brass to load for the M1A match.
You might check www.brassmanbrass.com as well and see his price on once fired .308, if he has any. I just bought 1500 once fired .223 cases from him.