Anybody that owns a car knows that a trip to the service shop is inevitable. It's pretty simple to do the basics, but the average car owner doesn't know anything about the size of their car's gas tank, let alone about what's under that hood. Although some good guys exist, many of the car dealerships and other mechanics see this as a chance to prey on the vulnerable and uneducated. We want to protect you from overpaying for parts and repairs you don't even need. Here are 10 Signs Your Mechanic Is Cheating You.