This is a heads up for anyone who finds a used iPad, iPhone, iPod, or Mac at an estate sale or a yard sale. Apple takes security very seriously and takes active steps to thwart thieves. A friend recently purchased an iPad at an estate sale and asked me to check it out. It was a series 5 iPad with cellular so a really good deal if it worked. All indications are it is working fine but I can't verify that because it is locked to the original owner. Without the Apple ID and Password, there is nothing that I can do to unlock it. I believe that Apple can unlock it but you would have to convince them that you own it legally and it is not stolen. Apple sets that bar high to protect us all.
Bottom line, before buying a used Apple product, make sure it works and is not locked by the original owner. The best scenario is the screen welcomes you as a new user and helps you set up your new device.