You don't get a code unless you buy a giftcode. You log into your non premium minecraft account and when you pay the premium is applied to that account and no other. You need to pay for each account you want premium on.
Oh i see so what privilege does a non premium account have?? you cant play with non non premium account?? its just a step 1 to buy a premium account? does it last for a life time? or do i have to renew it per year?
1. You are supporting the game of Minecraft and it's creators.
2. You are playing the game the right way that it's intended to be played.
3. You have to full version of the games and have access to multiplayer.
4. Much more. . .