I usually have lunch pretty cheap, but I feel there is a limit for the quality presented in a plate. Lunch today was tuna and potatoes, but when I looked at my plate I could only see potatoes lol. Something similar happened to you? What do you do in these cases?
I would suggest adding some colors on your plate. Add some fresh spinach or carrots or cucumber on the same plate where you are having your tuna+potatoes and you will find it more complete and fulfilling.
I've found that the best cheap meals are made of beans and/or rice. You can make a ton of recipes based around either of the ingredients, it's usually very cheap and very filling as well. One of the cheapest recipes I know consists of canned beans/baked beans, some seasoning and other stuff, and pasta.
Seasoning helps a lot. You can make a dish look better with the addition of some seasoning/spices. Also, you can make a variety of different dishes from potatoes, rice, beans, etc. just by changing the seasonings. I prefer tuna with pasta rather than potatoes. You might still see more pasta than tuna, but it tastes rather good, if you ask me. I used to make tuna and noodles quite often, both hot and cold varieties. You could also try making tuna cakes (similar to salmon patties) and serving that next to potatoes. That way, it looks more like a piece of meat on the plate.
To speak to the last post: Seasoning does not just make something look better. It doesn't just change the dish itself when you alter seasoning. It changes where it originated. I think that unto itself is immensely powerful.