If you want something hot, I'd do oatmeal. You can do a whole half a cup for 150 calories. I also like to add half a cup of unsweetened applesauce (50 cals) and maybe some cinnamon or sweetener if I want something sweeter. It's a huge portion and only 200 calories. Oatmeal is cheap.
Also, I love rice porridge (I just make it with rice and water). It's warm and tasty. I make it plain and eat it with an egg over easy or some ginger chicken. It's great for a nauseous stomach, too (the porridge, not the chicken).
Another rice dish I like that's sweet is chocolate rice. I make 1/4 cup rice (which is about 1/2 a cup when done), put in into a hot sauce pan and add 1/2 cup light soy milk. I heat until it's thick and porridge-y, and then add 2 tbsp sugar free chocolate syrup and a small dash of vanilla. Tasty! And only about 200 calories, again. Rice is pretty cheap. You could do this with regular milk, too.
That chocolate rice porridge sounds utterly tempting, but I should probably stay off artificial sweeteners as well as sugar, plus I could never wait that long for breakfast to be done!
I second both the oatmeal porridge and the rice porridge. I like to add a tablespoon of protein powder and a chopped date to my oatmeal, which gives oodles of protein (the date helps make up for the flavour). As for rice porridge, look up congee for ideas. I was gluten-free for a year, and I got into the habit of making congee with a mix I prepared of 2/3 Thai rice, 1/3 quinoa flakes, and a bit of sesame seeds. Then I put in frozen edamame beans, chopped carrots, and Savoy cabbage, plus a few seasonings (ginger, soya sauce). And now I really fancy some and I've just had supper. Ah well, maybe I'll feast on this for breakfast tomorrow.
My 2 favorites are oatmeal with a scoop of chocolate protein powder added after cooking (mmmm chocolate oats!) or Greek yogurt with a scoop of chocolate protein powder (mmm chocolate yogurt without added sugar!!). It depends really, if I'm working out in the morn then I go with the Greek yogurt as it's packed with protein but hardly any carbs so not heavy on my stomach
I love special K protein plus cereal. Cereal has always made me hungry, but the protein plus one by special k keeps me very full, and never have the sugar crash. I actually eat 2 servings for breakfast with cut up fresh strawberries or blueberries, I have even used frozen blueberries just letting them unthaw in the fridge before putting them in your cereal and I use unsweetned almond milk. Dont know what it is about this combo but keeps me super full and pretty tasty.
If you don't want to do sugar or artificial sweeteners, you can always use cocoa powder in the chocolate rice porridge. Especially if you use soy milk, that has enough sweetness for the whole thing (for me, anyway).
I think I tried something like that a while back, and found that I needed to add agave syrup. I don't generally use sweetened soya milk anyway; in the UK at least, it's not just the sugar, it's quite a lot higher in fat and generally in calories.
If you need something filling, I usually make "Bulky Oatie Meal" So its not its real recipe name, but it works for me.
1cup oatmeal
1 cup almond milk
1 apple chopped
cinnamon
dash of vanilla
chopped walnuts
cook the apple in the almond milk, add oats and cook.
its filling for not that many calories.