For some cars, a replacement battery from the dealer can cost more than twice as much as a comparable battery from a warehouse or auto parts store. Although there are many brands of car batteries out there, most of these brands are made by the same handful of manufacturers. These major manufacturers produce high quality replacement batteries that will usually perform just as well as an OEM (original Equipment Manufacturer) battery from the dealership.
Some dealers sell motor oil that is labeled with your particular car manufacturer's logo. Of course, auto manufacturers don't actually make their own oil. They simply buy it from one of the big suppliers, slap on their logo and sell it at a premium. As long as you buy a reputable brand of motor oil that meets the specifications found in your owner's manual, you will experience the same performance and oil life as the dealer brand.
Light bulbs burn out all the time, and replacements can be very expensive if you buy them from your dealer. Simple halogen bulbs can cost in the tens of dollars while xenon bulbs can cost hundreds. Dealer prices for these bulbs can be many times the price for comparable bulbs found online or at an auto parts store.
Dealers and tire chains often sell the exact same tires, except dealers tend to only carry the most expensive brands that have the highest profit margins. Whether you're looking for the expensive brands offered by the dealer or more reasonably priced brands, get some price quotes from the big tire chains, as well as some mom and pop shops. In some cases, you can save hundreds of dollars for the exact same tires.
When it gets hot outside, it's a good idea to cover your car in order to keep it cool and to protect the paint and interior. Your dealer will probably sell a car cover for your exact model that comes with a fancy logo, but that logo won't provide any extra protection for your car. You can find a high quality cover at an auto parts store, a retail outlet or online for a quarter of the dealer price.
Stan Markuze is the founder of PartMyRide.com, the online marketplace for original used auto parts.