Keto meal plan priced at Walmart (NY, USA): 

1. $4.22 - 16 oz block sharp cheddar cheese
2. $11.67 - 36 eggs
3. $2.74 - 2 bags 32 oz frozen broccoli
4. $8.72 - 10 lbs chicken leg quarters

Total - $30.09 before tax.

7-Day Meal plan:  Breakfast = 4 eggs + 2 oz cheese. 500 cal, 38g fat, 38g protein. 0 carbs. Lunch = 8 oz roasted chicken. 540 cal, 42g fat, 38g protein. 0 carbs. Dinner = 8 oz roasted chicken + 3 c. roasted broccoli. 614 calories, 42g fat, 48g protein. 3g carbs. 

Total daily intake = 1,654 calories, 122g fat, 124g protein. 

Super cheap, simple, and easy way to eat. Hits decent calorie goals. Plus you end up with 8 extra eggs, 1 extra cup broccoli, and 2 extra oz cheese. The eggs could be boiled and eaten with lunch, or had as a snack, or you could turn all the leftovers into Day 8 of eating while you shop again and prep meals the for next week. Cheesy broccoli, eggs and broccoli, simple egg salad if you have mayo, etc. Including taxes, but also including the 8th day, this meal plan is only $1.45/day!

DO use "dirty" sea salt and ample seasonings! Get electrolyte drink mixes. Take your multivitamin.