About $20/day is pretty reasonable for carnivore  

You can go extra budget with eggs, butter & 70/30 ground beef but GF steaks puts you up a bit  

I also go mostly grass-fed but couldn't resist some steaks from the discount bin of a mega-chain this week (beautiful ribeye for $10 each) 

 I manage about $10 a day with 1lb GF beef mince and a few eggs on my cheapest days. Eating once a day saves a ton of money apparently.