First, I will say, I love to cook and I love trying new foods. My personal choices for cooking may be more ambitious than someone who isn't enamoured with cooking. But even with that in mind, there are still several ways to cook a meal with regards to the environment and budget.
There are pages and pages available on environmentally correct dining. I'm not going to go there. Instead I will offer the simplest easiest tip I can. Shop your pantry and freezer/refrigerator. Do NOT run to the store for "one item" in a recipe. Improvise. Be adventurous. Go meatless a few meals a week. Fill your pantry with canned beans, whole grain pasta, and spices for a quick protein fix that will not spoil. A shocking statistic that will make you reconsider meat at every meal? A pound of beef requires around 12,000 gallons of water to produce, compared to 60 gallons for a pound of potatoes.
My favorite surprise under the "What's for Dinner" category is to look at 3 random ingredients I already have. I type those ingredients into a search engine and scan the recipes. This is also a fabulous way to use up fresh ingredients before they spoil. (and if your fruit/veggies start to go bad, do NOT throw them out, but compost them, which will be another post, tomorrow).
One night, I served a lasagna with Texturized Vegetable Protein (dried soy nuggets that when reconstituted has the feel of ground beef), cottage cheese, and fresh tomatoes. It was fantastic! I've found some real hits that have become family favorites. I keep a blog with another writer friend of mine, Cooking With Superfoods that lists several of those sorts of recipes. We try to inspire each other with healthy eating and simple recipes.
A few moments of thoughtful planning before a meal and an adventurous palate will fill your stomachs in a budget friendly and environmentally happy way.