Midway has a deal going on today for 400 rounds of Sellier & Bellot Garand-safe 30-06 ammo for $250. Shipping for me was an additional $16. You could probably get the shipping down a little lower by adding on one of their free shipping items.
That brings it to a price of about $0.67/round, which is cheaper than the current CMP price on their 200 loose round ammo cans of HXP ($0.73/round)
http://www.midwayusa.com/product/359819 ... _-20170223