I forgot prices...

The price of 6.5 Grendel varies from (regular prices, available ammo):

$0.95 per round with a 50 round box of Federal American Eagle 90gr JHP.
to
$1.62 per round with a 20 round box of Alexander Arms 129gr Hornady SST.

6.8 SPC varies from:

$0.86 per round with a 20 round box of Federal American Eagle 115gr FMJ.
to
$2.30 per round with a 20 round box of Doubletap 110gr Barnes Triple-Shock X-Bullet hollowpoint lead free.

.300 Blackout goes from:

$0.50 per round with a 200 round box of Magtech First Defense 123gr FMJ.
to
$2.05 per round with a 20 round box of Noveske 220gr subsonic ballistic glow tip.