Oil is known as black gold, which is why anyone can become an oil tycoon by submerging a heap of gold watches in a mud puddle. Enjoy one of oil's many golden uses with today's Groupon: for $15, you get a full-service oil change at Classic Car Wash and Mobil 1 Oil Change in West Roxbury (a $34.95 value).

With more than 30 years of experience in the car-care industry, pit-worthy crews at Classic Car Wash and Mobil 1 Oil Change meld customer service with the latest lubrication technologies. The full-service oil change drains tired old engine juice and replaces it with up to 5 quarts of standard oil (synthetic, high-mileage, and coconut-scented baseball-glove oil are extra). After installing a new filter and lubing the chassis, an automotive artisan checks and fills all fluids and inspects every light's power of illumination. Lastly, the air pump inflates tires to an optimal road-ruling pressure without overinflating their egos and making them unbearably rude to neighboring hubcaps.