I see where a major online gun dealer now advertises Aguila .223 rifle ammo for $349.95 per 1000 round case. I recall another retailer had the same stuff for around $270 a case just four months ago.
I also see Sportsman's Guide is selling Federal 5.56 55-grain ammo on strippers for $280 per 900 rounds. That's a good price, but it's on back order. They don't anticipate taking delivery until late October. If you'd ordered four months ago, it would have likely been delivered to your doorstep in five to seven days.