AutoZone is America's favorite auto parts store, selling more than $8.1 billion worth every year. Whether you are looking to kick-start an engine rebuild or perform simple maintenance, great AutoZone deals can be had on GTX motor oil, Duralast parts, and all the tools you might need for the job. The company's mobile apps can help locate the nearest store, find the right parts and AutoZone coupons, and access your vehicle's repair guide. The company also offers free diagnostics tests whenever your car's pesky "check engine" light starts blinking.