There’s a ramen sauce that makes ramen soup I like. Add that to just the dry noodles they sell- not the packs of ramen- and it’s very economical and better quality.

Anything works in ramen. If you have a freezer I’d suggest ham is a very very cheap protein to add if you can buy in a large size.

Otherwise, sprouts are good and inexpensive. So are mushrooms. Turkey is cheap but in bulk like ham. If you’re aiming for less bulk chicken thighs are inexpensive and good in soups.

If you brine your eggs in mirin and soy sauce they will work even better in the dish.