IIm thinking of buying a used iPhone 4s?

IIm thinking of buying a used iPhone 4s and I don't know if it's stolen or not and don't know how to check and I just want to be sure because I've heard stories, it has the iPhone 4s box with it along with the charger, also it's on the set up screen still where it says the big giant "HELLO". And also, because it's an iPhone, can I set it up without using a cell phone plan and just use Wi-Fi 24/7?

Before you buy a phone, make sure that it's IMEI/MEID isn't blacklisted. This number is a unique identifier that all phones in the world have.

You can check the IMEI status by going to a website like: https://www.swappa.com/esn
The IMEI number can be found by pressing on the little "i" on the bottom right corner of the "Hello" screen.

However, to be 100% that the phone is good, arrange with the seller to meet at a cell phone store, so if the phone is from AT&T, meet at an AT&T store, etc. And have the verify that the IMEI is clean and ready to be activated.

Next thing to check is the iCloud lock status. You have to do this on a computer by going to: https://www.icloud.com/...ationlock/ and by typing in the required info. If it comes up as "On/Activated" Don't buy the phone.

To answer the last part, you can use the iPhone as an iPod, however, for the initial setup process, you have to use a SIM card that is from the phone's carrier. In other words, if the iPhone is from AT&T, you have to use an AT&T SIM in order to continue with the setup process. You only need it once, though.