How to install Minecraft free?

You don't.
You have to buy the game.

They have a demo on their website - https://minecraft.net/...t.net/demo

Alternatively you can download a free alternative Minetest- http://www.minetest.net/

Other than that you're not getting a free minecraft premium account. Nobody buys accounts and gives them to strangers on the Internet.

Without online?
heres the link! https://piratebay.co.in/torrent/12172451/Minecraft_1.8.8_Cracked_%5BFull_Installer%5D_%5BOnline%5D_%5BServer_List%5D
i think it can be done with online too!