Will sprint replace a stolen iPhone?

Sure, as long as you pay for it.

Why would they give you a free one?

Ask Sprint. I know some carriers offer insurance that covers stolen phones, but if you didn't get such a plan I can almost guarantee you they will NOT replace it.

No. If you purchased insurance, then the insurance company will pay to have it replaced. Sprint isn't responsible for your negligence or carelessness. Call the police and report the theft.

How can they call the police, their phone was stolen 😝