When and where will be available water from broadcast Water Pack Overview, New Launcher & More | News | Unreal Engine - YouTube ? Cause nobody mentioned it or I missed something.
A few weeks, I think is coming with 4.7, just a speculation.
How much will it cost???
Free, and it will likely be added to the Learn tab of the launcher soon. 
Moving thread to General Discussion since is not a marketplace item.
If you don’t want to wait you may want to check out my Advanced Material Pack Edition 1 which is on the marketplace already.
I have water materials in there which do the exact same thing but they are completely driven by instances rather than BluePrints + Instances.
https://forums.unrealengine.com/showthread.php?37089-Advanced-Material-Pack-Submitted