What in the world is a friend key? Can someone give me one please?

A friend key will give you 2 weeks of Premium access [edit]. You must provide an email address for the key to be sent to. People usually prefer to give their email address in-game over private message.

If you choose to post your email address here, once you receive your key you may want to delete your post that contains your email address; we've been visited by bots before, although it is uncommon.

Oh ok. I thought friend keys can access something inside the game.

Errm, phaser? The account does not have to have been created on PC. A friend key gives you 2 weeks premium. Regardless of account type/device.

Oh! I stand corrected. Glad that Doom Turtle will be able to use those keys I sent him, then.

They do only work if you have never been subscribed or used a friend key in the past. DT has been I think? I could be wrong.