UE 4 is now FREE?

Unreal Engine 4 is now available to everyone for free.

But how it works?

If I need to create TV commercial using UE4 for 3D environment, I only need to pay
subscription - $19 per month or ?

And whether it related to this:
When you ship a game or application, you pay a 5% royalty on gross revenue after the first $3,000 per product, per quarter.

If anyone can explain better,

All details here, information is pretty straightforward, so give it a try.

You pay only royalty, nothing more.