I ordered an iPad mini 3 with cellular from Best Buy to replace my wife's broken iPad mini 2. She had a Verizon model, but used T-Mobile on the iPad mini 2 because she rarely uses cellular service -- so the free 200mb per month on T-Mobile was enough. She wants to do the same for the iPad Mini 3, but I am a little confused about how the Apple Sim will work and what to do for maximum future flexibility. I understand that if she ever wants to use the iPad on Verizon, cellular service must be set up with them first. Is this possible for an iPad purchased from BB or do you need to purchase an iPad from Verizon if you want the future option of using Verizon service? Also, will we need a T-mobile SIM to get the free 200mb without signing up for another T-mobile prepaid package or can that be done using the Apple Sim that comes with the iPad?