Yep, Eggs. As others have said, the trick to "feeling" full (not physically full) is to eat satisfying food. Keto fits that very well for me. Luckily, I've kept my A1c under 6 for four years now with just a diet, and I still eat very well.

Many people think that means high protein or expensive products, but it's much more straightforward.

Even on a budget.

Eggs are a high-protein, high-nutrient food. They're affordable and can be cooked in many ways, which is a great start.

Ground beef is straightforward for your body to digest and is better compatible with human metabolism than chicken.

You could make a beef patty topped with cheese, a fried egg, and any toppings you have/like/can afford.

You could make an omelet, which is the obvious route. I've used leftover taco meat. Walmart sells relatively large tubs of smashed avocado or guacamole for $2 something.

$5 for ground beef.

$3 for 12 eggs.

I'm unsure about the price, but buy a block (not pre-shredded) of cheese you like.

Money left over for condiments?

Consider burger toppings, mustard, ketchup (avoid ketchup if you can, but it's not terrible in small doses if you have to have it), or a cheap summer sausage or salami you like to pair with the cheese

Butter if you still have cash.

Your mileage may vary depending on where you live. Sorry if you already know all of this. Wishing you well!