I think you're doing something wrong if making food from scratch is more expensive than a prepackaged product, assuming you have the tools and whatnot already and are only comparing ingredients.
For example, I can buy plain yogurt for about $3-4/half gallon, or I can buy milk for $3-4/gallon and make the yogurt myself. So yogurt, which should be easy to mass produce, is about twice the cost packaged vs made from scratch.
The same is true for more complicated dishes, it's just a lot harder to calculate since there's a lot of spices and whatnot left over after making a given meal.
Are you sure you're comparing the same quantity/quality?
filler
I tend to add eggs to lots of things. For example:
- pancakes - add an extra egg to the batter, or fry an egg and put it in top
- ramen - add fried egg on top
- brothy soups - stir in an egg
Eggs are pretty inexpensive in my area, so YMMV.