Grendel factory ammo is scarce and the most expensive. Its probably the least available ar15 caliber that isnt big bore(.458 and .50beo more rare)
I see 2-3x the amount of in stock 6.8, .224 valkyrie, .300blk etc
Wgs brings in small amounts of wolf for grendel but hes out and its around 50 cents each instead of the .25 cents people online get em for. That moves it from .223 steel case price to .308 brass old surplus price. He only has some $3 a round grendel in stock as of last week.
Starline brass is $.50 each shipped and hornady 123gr sst is 30 per 100.
Besides wolf steel, youre looking at $1.50 per round for american eagle, hornady black etc.