You can make it even cheaper by securing yourself a parcel of unclaimed land, stealing some animals, building a small shack, and then growing all the vegetables yourself!

A cheeseburger from McDonald's is $2 × 3 = $6. You can buy a large fries for $3 and split it. Steal handfuls of ketchup and salt. $9 to feed your family of three. You can even buy a large soda and split it, ya bourgeoisie fuck, and it took you no energy or time to cook it, instead of the 1+ hour it took to make yours.