Is that Free Phone Really Free?

Are free phone deals free, or too good to be true?

Yes and No.

Here are the most common requirements that you must meet to get a free phone: 
After meeting all the required conditions, is it really, FREE?

1. You need the right phone to trade in.
2. You need to sign up for a qualifying unlimited plan
3. Monthly bill credits are part of a long-term contract requirement
4. You must be deemed Credit Worthy by the phone company
5. You must pay a fee at Checkout
   

So, are free phones free?

It's complicated, but at the end of the day, the answer is most likely "No." You either must give up something you currently own, like your existing smartphone, or you have to sign up for a monthly plan that may be overkill for your personal use. 

And depending on the installment plan a promotion requires, any changes you make could jeopardize your monthly credits, which means you will owe your carrier the remaining balance to cover the cost of the phone.

https://www.zdnet.com/article/are-free-phone-deals-really-free-or-too-good-to-be-true/