Arm & Hammer Advance White Toothpaste, $3.60 for 4.3 Ounces

With peroxide to whiten and baking soda to clean, this paste releases penetrating bubbles and leaves a minty taste that lasts after you brush. “It brightened my coffee-stained teeth and didn’t make them sensitive,” said one tester.
Time Commitment: The two minutes it takes to brush.
To Buy: At drugstores.