Can I sell my iPhone? Is it unlocked now?

A few months ago I finally upgraded to an iPhone5s and now I just have my old iPhone4 sitting in my drawers and I want to sell it. Is it unlocked now that I have a new phone? I have Sprint as my service.

At&t allows you to unlock it on their website, see if sprint has the same, then say its unlocked when you sell it as that will be in higher demand

Sure, you can sell anything you wanna sell.

No it is not unlocked, you can still sell the device online. Sprint had/has a thing in their contracts that they do not sell/or unlock phones. There are a few cell phone specific sale sites but those are a bit iffy imo. Just post on ebay and see what happens, iphones are always in demand and I assume it will sell in no time (just make sure to do a factory reset before you ship it!)

Sure why not

It is not unlocked, but if it is already off the contract, you can definitely sell it now. There are plenty of online websites that buy those phones.