Ammo the government didn't buy up first.....

http://www.ramarmory.com/RAM-Arms-ammunition-s/2076.htm

And then there's this for your reading pleasure (or aggravation, if you live in California)....

http://www.typicalshooter.com/

They had a box 0f .223, 1000 rounds, for 400.00 at Walmart the other day.  I was impressed.  They seem to have a boxes like that now and then, but somewhat regularly.  Low-end .223 AR-15 knockoff for about 620.00 too.  Not a bad setup for 1000 bucks total.