I know this sounds like a really stupid question to ask. However I am very new to this and have no idea what to do. I have an old phone, and I have no idea what it means to have an "unlocked" phone. People keep telling me I need one in order to use bought sim cards to verify instagram accounts. The questions are. What is an unlocked phone and how do I do it? When I buy sim cards do I just put them in my phone and activate them? My phone is verizon, do I have to buy only verizon sim cards? Somebody please explain this to me because I want to make sure before I buy a bunch of sim cards.