What do I do with a found Iphone 4s (Verizon)?

I bought the phone from Craigslist that was reset. The Sim card was removed. I want to use it or sell it legally. What do I need to do?

Put in your own sim card

If you found the phone you need to return it to Verizon. This phone is blocked and will not be able to be reactivated.

It's legal to sell it you know. There's nothing stopping it because you paid for the phone and so its yours. Selling the Sim Card or a phone with the Sim Card is another deal. If those are your two main options then there are a few things you could do. You could resell it to a friend, person, trade it in for a new phone, young person who would like such a device without the data or calling abilities. Another thing possible is to simply buy or use an existing Sim Card ans insert it so it can be your phone. Another thing is that if you have a phone already (not the 4s) you can simply store the phone and keep it as a backup in case the current one is damaged beyond use. You may also jailbreak and unlock it so you can use it with other carriers or in other countries with the native carriers there already. If you don't want to spend any money on the sim card than there's one last option to make it a still usable phone. After you jailbreak it (unlocking is not required for this) download an app (there are many) from either the normal App Store or Cydia that allows for calling and texting without the use of a sim.