Here's an easy way to cook your own meals regularly, and not spend too much time or money on it. This is based on mexican food, but there are other cuisines where you can do similar things. I might write articles for different ethnicities later. There are a few things you need in your pantry that you may not have, and four things to cook ahead, but not all of the four have to be cooked at one time.

The idea is to keep a few basics on hand, and combine them in different ways to make a variety of things. The secret is to make as much of each basic food as you will eat before it goes bad, so you don't have to cook it as often.

Your pantry should have:
Cans of diced tomatoes
Cans of pinto beans
Chicken broth (or you can use bouillon; it's cheaper but has to be mixed up each time you use it)
Rice
Cumin, and lots of it (this can usually be bought in larger quantities for less money at mexican or asian grocery stores)
Chili powder

Your fridge should have:
Salsa
Tortillas
Monterey Jack cheese
Lettuce (optional)
Chicken (whatever part is cheapest)
Ground beef
Onion

Foundation recipes:

Refried beans:
Take one or more cans of pinto beans (include the liquid) and add about 2 teaspoons of cumin, plus chili powder and salt to taste. Cook (the heat level isn't important), stirring frequently, for 5-10 minutes, just enough to let the flavors mingle. Put all of this in the blender or food processor. Add water if it's too dry.
Refried beans will keep for 2-3 weeks in the fridge. They can be made with just about any type of bean, if you want to try something different for variety.

Mexican Rice:
This one's easiest if you have a rice cooker, but you can do it on the stove.
First, heat a pan to high heat on the stove. Add a little oil and cook a handful of chopped onion until it's soft.
Follow the instructions with your rice cooker (or on the bag of rice if you're cooking on the stove), but substitute chicken broth for the water. Add about a teaspoon of cumin per cup of dry rice, and a little less chili powder (about 1/2-3/4 teaspoon per cup of rice). Add the onions you already cooked. Let the rice cook as usual. Add canned diced tomatoes (liquid included) to the cooked rice; you want about a half a can per cup of dry rice you used. Stir that into the rice, and you're done.
This will keep 2-3 weeks in the fridge as well.

Chicken filling:
Boil the chicken until it starts falling apart. Then drain it (you can keep the liquid and freeze it for use in the rice if you like, but if you do that, add some salt to it before freezing). Pull the chicken apart with forks, into smaller-than-bite-sized pieces. Cut it up with a knife if you need. Heat a frying pan over high heat. Add a tablespoon or two of oil, and some chopped onion (to taste). Cook the onion till soft. Add the chicken and some cumin, chili powder, salt, and pepper. Start with small amounts of the spices and add more until it tastes the way you like it. Once you get the spices right, cook it for another minute or so, adding a few tablespoons of water if it's getting too dry, and then it's done.
This will keep for 1-2 weeks in the fridge.

Beef filling:
Heat a frying pan over high heat. Add a tablespoon or two of oil, and some chopped onion (to taste). Cook the onion till soft. (Sound familiar?) Add some ground beef, and stir/chop it until all the pink is gone. Drain off some fat if you'd like it lower-fat. Add spices the same way as with the chicken.
This will keep for 1-2 weeks in the fridge.

The meals you can make:
Tacos (beef or chicken or bean)
Burritos (beef or chicken or bean)
Quesadillas (beef or chicken or plain)
Enchiladas (if you also buy or make enchilada sauce)
Each of these can have refried beans and/or rice served as sides.

Tacos: Microwave 6" tortillas briefly so they're warm and soft. Fill with your choice of the following: meat and/or beans, salsa, lettuce, and cheese.

Burritos: Similar to tacos, but use 12" tortillas. Put your choice of fillings in a line at the center, leaving a couple inches empty at one end. I also like to add rice to my burritos. Fold the empty end of the tortilla over the toppings, and then fold or roll the sides in.

Quesadillas: Heat a pan over medium-low heat. Put chicken or beef filling (optional), and plenty of cheese between two tortillas, or in one, folded over. Cook for about 2 minutes per side, just until the cheese is good and melty.

Enchiladas: Use 6" tortillas and put your choice of meat, beans, and cheese along the middle. Roll them up, and put them on a plate. Put enchilada sauce over the top, and sprinkle cheese over top of that. Microwave for a couple minutes.