IMO egg yolk covers most of what you'd want from organ meat. I am not a fan of gizzard. Another option is salmon roe, which is objectively quite expensive but a spoonful with breakfast will cost you maybe $10/week.
I'm able to get grass fed beef liver for something like $4 per pound, and a little goes a long way. I've seen beef liver at Walmart for $2 per pound.
Ground beef can be had for about $4/lb where I am, specifically 70/30 which is what I prefer/recommend anyway. I am mostly grass fed now (which is usually ground leaner) but I don't think finishing feed makes a huge difference.
I get chuck roasts ($4 a pound for choice, I get grass-fed which is like $10 per pound) and cut them into steaks. Not quite as much fat as something like a ribeye but some marbling and more flavorful meat.
Mussels are an excellent budget option - I can get 1lb of frozen mussels for $4.
My wild salmon I get frozen from my grocer at $16/lb, thaw and cut into poke-style cubes. Then I just eat it raw.
If you tolerate milk well, cream is a very cost-efficient calorie source. Just be sure to check for additives. Half & half is more readily available without additives.
IMO $10/day can get you a basic carnivore diet, while $20 gets you to grass-fed pasture raised etc and $30 gets you all that plus some mix of caviar, fine sausages, fine cheeses, etc