I don't really make my lunch, but something that is extremely cost effective is chicken soup. You can eat it probably 20 times and it costs around $40-$60 to make. It also keeps really well. The recipe is somewhat involved, but the value you get for it is worth it.
Ingredients
*Buy a whole chicken (by far the cheapest way to buy chicken and also the most flavorful).
*2 16 oz. cans of peeled or diced tomatoes
*1 large stalk of celery
*1 package of whole carrots
*1 bag of medium red potatoes
*1 cup of parsley
*1 cup of cilantro
*2 cups of mexican salsa
*1 medium size red onion
*Salt and pepper to taste
*Optionally: 1 package of uncooked biscuits (the cylindrical one that's under pressure), cut the biscuits into thirds.
Requires: One large cooking pot or 2 medium sized cooking pots if you cook the potatoes separately.
Recipe: If you don't have a large enough soup pot start boiling the potatoes in salt water first. Remove water and set aside after 30 minutes. Add the potatoes after deboning the chicken (below).
*slice the carrots, celery, and onion into 1/4-1/2 inch pieces (medium bias) and place in bottom of pot.
*finely cut the cilantro and parsley and put in bottom of pot
*place canned tomatoes in bottom of pot
*Remove chicken from packaging and drain any liquid. Place whole chicken in pot on top of the vegetables. Fill the pot with water up to the top of the chicken. Add a quarter cup of salt (or less if you don't like sodium in your diet) and a tablespoon of pepper.
*Place pot on stove top on high heat until boiling. Reduce heat to medium so that it is lightly boiling and cover for about 45-60 minutes until chicken is thoroughly cooked. You can tell by stabbing it with a fork or pulling on the bone. If the meat easily begins to fall of the bone then it's done. Allow the soup to cool to around room temperature. You can place it in the fridge after 10 minutes to speed up the process. Once the chicken is cool enough to hadnle, take a fork or wooden soup spoon and put it through the neck hole of the chicken and remove it from the soup and put it on a tray. Pull 2-4 inch pieces of chicken of the bone with a fork and knife and place them in the pot until the chicken is thoroughly deboned then dispose of the bones.
*If you boiled the potatoes separately, you can now place them in the soup at this point as the volume will be greatly reduced.
*Add salsa and more diced parsley and cilantro if there is any left.
*Put the pot on high heat again until boiling. If you have the cut up biscuits you can now place them in the pot. Reduce to medium heat so that it is lightly boiling and cover again for at least 30 minutes. If you are using biscuits wait until they no longer float to the very top. If your water level is low you can add more. If you don't like how fatty the soup tastes you can allow it to cool and and skim the fat off the surface with a spoon or small cup.
*Serve. Add salt and pepper to the bowl if necessary. It should last for a week or two. Keep it in the fridge and transfer cold soup to a bowl or thermos and microwave it when you get to work.