Buy the cheaper cuts of meat, mince, turkey, chicken, etc and you can go even cheaper by shopping at places like Iceland or FarmFoods or any other frozen food shop, another diabetic on low carb buys cheap chicken/boiling fowl and makes broths and soups and casseroles from this with chunks of meat in it, she swears as this being good comfort food on cold weather days.
I dont eat meat, I have eggs, cheese and fish, dairy products, kefir and nuts - I often buy frozen fish, its cheaper or tinned fish, shop at Aldi, Netto or Lidl, buy frozen vegetables, they are sometimes fresher than the veggies that hang around supermarket shelves for a few days.
Fill up on more vegetables, depending how low carb you are going, have some porridge (the steel cut oats), a small amount will fill you up.
All the best
Karen