This one is a personal favorite. It practically comes free, especially if you regularly brew and drink coffee.
Instead of throwing away your coffee grounds every morning, save a batch. I suggest doing this on a weekend, to de-stress. Use it in the shower, after soaping up. Scrub the grounds on your hands and feet, concentrating on the heels and other rough spots. If your coffee is finely ground, feel free to use it on your body. After gently rubbing it all over your skin, you can leave it on a few minutes and inhale the aroma of your favorite blend. Rinse off the grounds when done. Don't soap off anymore afterwards. The natural oil in the coffee will moisturize your skin. If like me, you get some random brown spots or streaks on your skin, simply rub it off with your fingers under running water. After drying off, your skin will feel softer and more supple.
Another take on plain coffee would be to use slightly drier grounds and mixing in some brown sugar or honey. Honey is especially good because it has natural anti-fungal, anti-viral and anti-bacterial properties. Smells great too :)
Spas here are now starting to offer coffee scrubs. By using your own, you save a ton of money and reuse the grounds, helping save the environment. Go a step further, and don't throw the grounds on the other days either. Dump them in your compost pit. Use it as fertilizer, and sprinkle it over your grass or plants.