Cheapest foods per calorie (healthy)

Cabbage.... cook in oven with tomato sauce and pepper. Not high in calories but the fibre fills you up completely. Add ground turkey in it for extra . You will be suprised how filling it is. I shred it so that its almost like eating a pasta. delish

Look around your area and see if there's an Asian grocery somewhere. I find the best prices there on large quantities of raw almonds, long grain brown rice, and spices. For example, for the price of a tiny plastic shaker of Turmuric in a regular grocery store I can buy nearly a pound of it at the Asian grocery.

I think that your ideas are great, and if you want to keep the lower calorie fresh veggies cheaper, adding oil is a great way to do it. I can have a serving of fresh green beans or asparagus for only 20 calories but add 1 T of oil and you've added 120 calories for very cheap. You can get a 3 L of olive oil at Sam's club for about $15, which comes out to about $.63 per 1000 calories. If you went with a cheaper oil, you could probably get your 1000 calories for half that price. Over the course of the day, you could use 3 T of oil fairly easily without making your food too "greasy". Use 1 t to cook your omelette in the morning, drizzle 1 T over your salad at lunch, when you have meat, add oil, use it to cook your veggies, etc. I've even known people who've added "flavorless" oils to smoothies and oatmeal. That would add 300-400 calories to your day easily and for only about $.25-.35.

I also like to use cheese. I can buy a 2.5 lb block of sharp cheddar at Sam's club for about $6. That means that it's actually about $1.25 per 1000 calories, but when you add it to dishes, it's fairly cheap and very flavorful. If you add an ounce or two of cheese throughout your day, you've added another 200 calories for about $.25.