The terms used, OEM, OEM, and aftermarket might be interchangeable to most drivers, but if you’re looking for a new set of car headlights or taillights, it pays to know what these labels mean. Let’s take a quick look at these common phrases. After all, who doesn’t want to save money when buying parts? I searched for high quality used tail lights for sale on Google today. And I got around 2,000 results in 0.35 seconds (as shown below). That means used tail lights are very popular among customers. They search used parts on Google everyday to find out how much they can save by using used parts instead of new ones.