I'm looking at getting a Samsung Galaxy S7 hopefully. But there are lots of them out there.. some with different criteria though... such as locked and unlocked. I don't know what that means... I don't want to pay for a phone, get it, and have it not work... that would be bad. I hope someone can offer advice. Thanks.
You need the IMEI number so you can check to see if the device is compatible. You can do that at vzw.com > shop > smartphones and devices > bring your own device. Just select I am not a customer then enter the IMEI. If it's a Verizon phone you'll want to call customer service to make sure it's not reported stolen, or on some kind of non pay list. It doesn't need to be a prepaid phone, but it's easier if it's a vzw phone. Phones bought through private sale can end up on lost/stolen lists or non pay lists after you've bought them, so you're taking a risk doing it that way.