Ground beef: $3.50/lb = $2.19/day
Sardines: $9.99 for 6 - 4.375 oz = $1.67/can = $1.67/day
Fresh spinach: $3.99/2.5 lb (.35 cents/g) = $.84/day
Eggs: $7.99/ 5 dozen (13.3 cents/egg) = $.40/day
Sunflower seeds: $2.49/lb = $.36/day
Butter: $9.99 for 4lbs = $2.50/lb = $.12 cents/day
Total cost: $5.58/day
This is 1800 calories and is 65% fat, 30% protein, and 5% carbohydrate. I used http://nutritiondata.self.com to formulate it and it meets or (far) exceeds every vitamin and mineral requirement except for only 50% DV of Thiamin (not worried about this).
I basically do a version of this but with more expensive boneless short rib (very marbled and delicious) and am in perfect shape (you can find evidence here if you scroll down a bit https://twitter.com/FoodLiesOrg )
Spreading this menu over 2 meals (one at noon and one at 7:30pm) will give you a nice intermittent fast. It will also train your body to burn fat instead of sugar. You will be very full off of only 1800 calories and should lose a lot of weight.
Disclaimer: I'm not dispensing nutritional advice as I am not a doctor or dietician. I've just researched this stuff for years and am making the documentary http://foodlies.org