101 easy ways to save energy, money, and the environment. By far the simplest and most cost effective thing you can do is use compact florescent light bulbs throughout your house. They can save a ton of energy and eventually money. The one issue with these bulbs is that they contain a small amount of mercury. So it's important that you don't throw them out, you need to get rid of them properly. Hopefully as the technology advances, the mercury levels get smaller.