For my birthday, my sister-in-law got me The Keeper, which I absolutely love. If you don't know what The Keeper is, it's a reusable feminine hygiene product (aka a latex cup. super cool).
It's environmentally and economically friendly. At $35, they're supposed to last for 10 years. I'd say that's a lot better than buying a $5 box of tampons every month. Not only are you saving money, you're saving the environment by decreasing amount of waste produced. Additionally, there's no chance of Toxic Shock Syndrome like there is with tampons. How can The Keeper be a bad idea? They also make Moon Cups, which are latex free, for people with allergies. Another company makes latex free Diva Cups.
I love my Keeper and I want to give one to every woman I know. Plus, they come in a cute bag! But seriously. Good for the environment, good for your wallet, good for you.