QUOTE(Ckmwpy0370 @ Aug 6 2017, 02:33 PM)
yes you are right.
but is it necessary need private IP for home use?
For example: in big organization like my office, yes we need to have private IP for our Local Network ans WAN network with VPN connection.
Bro, I think you are slightly confused or I might have misinterpreted what you meant, it's usually private IP that is FOC, and you have to request for public IP.
Also, you are already using private IP for your local network, and it's only your WAN IP that is public, using NAT.
So, for example, all your devices in your LAN are private IP, either 10.0.x.x or 192.168.x.x, but all of them are sharing one main WAN IP, which could be anything EXCEPT 10.0.x.x or 192.168.x.x, or anything between 172.16.x.x - 172.31.x.x, which are all private IP ranges. This is a process knows as Network Address Translation.