Who doesn't enjoy the tepid, slightly sour smell of morning breath? If that concerns you, the Kiss Me Meter measures sulfur-based compounds that get left behind after eating. There's five levels of mouth smells (Gadzooks!) that the Kiss Me Meter measures and different colored LEDs light in to warn you that all is not well. The meter can even be re-calibrated just in case it starts playing tricks with your ratings. The Kiss Me Meter can also be used as an alcohol breath test.
The Kiss Me Meter is small enough to fit on your keychain as well. The battery should last for more than 150 individual uses. Its creator doesn't list a price, but like those credit card commercials say, having non-offensive breath is pretty much priceless.