Meat is cheap because the more portion is meat, the less calories you consume.
Vegetables are cheap, but high in carbs. Stick with low carb vegetablea like cabbage and broccali.
Herbs are expensive. Salads are a waste of time.
Grains seem cheap, but they make you eat more.
Never eat food supplimented with artificial vitamins, it makes you overeat. Many kinds of rice have vitamins added, its on the label.
Pay attention to foods that keep you full longer, v.s. those that don't stick with you. Try to eat the long lasting foods.
If you eat too late, many of those calories are wasted during sleep. Better to eat once or twice per day, for example 2pm and 6pm. Fast the rest of the day, and go to sleep early. People tend to be too busy to eat in the morning, best to take advantage of that and just eat in the latter half of the day.
Caffeine makes you crave sugar and carbs, limit it to the first half of the day when you don't have time to eat. High carb foods tend to be highly prepared, which equates to high cost.
Obviously, never buy anything in a box, whether its in the middle of the store or in the frozen section. They always cost more than the food value inside.
Pertaining to dairy: I personally think none of it is necessary, it has little food value, doesen't stick with you, makes your nose run, hard on your immune system, and is expensive. Regardless, we're going to eat it anyway, so try to use it as an ingredient in a dish rather than putting it out in a bowl.
Snacks? Carrots and celery.
Don't like celery? Then carrots and rice.
Don't like carrots? Its because youre buying the wrong ones. Simply organic isn't enough. You need carrots that are loaded with nutrients. You can tell those by their shape. If they're bif, fat, and odd shaped, that's because they are grown in real soil rather than peat koss. Real soil has nutrients that carrots can harness to make them taste delicious.
Beef too expensive? Buy fish.
Avoid chicken and pork if you can, they are high in lineoleic acid which is the same as the bad seed oils.