One thing I've decided to do here is include the cost of each ingredient to the recipes and directions provided in this blog. Things you've made at home yourself taste better than anything pre-made from a package, are better for you, and are generally less expensive. When and where applicable, I'll try to provide a packaged analog to compare ingredients and price. All prices, unless stated otherwise, are taken from Netgrocer. Typically, I'll take the price per ounce of each ingredient and figure how much per recipe, item by item. Your prices may vary some, especially if you're outside of the U.S.
Some things I won't provide the prices for, like occasional sprays of oil, pieces of parchment paper or plastic wrap, and water. It's silly to try to subdivide all that, and not useful. And, as mentioned before, baking requires tools. A modest investment will go a long way toward your budget in the long run, as well as your health. What you put into your body is your responsibility, and a vital part of good health is eating the right things that you yourself have prepared.