Can u get banned for life if you say gg ez?

Short answer: Yes

Long answer: You would have to progress through the ban phases as normal (you won't skip to the end) but if you say gg ez after every game you win, there is a chance that you will eventually be banned as it has been deemed by Riot to be toxic.

No, there are no "bans for life" in League of Legends. You can always come back with a new account.

Edit: I do not believe there is any information on ban tiers currently. AFAIK, there are chat restrictions, ranked restrictions, 14-day bans, and permanent bans.

Back with the second tribunal iteration, it used to go Warning >>3-day>>1-week>>2-week>>Riot Review

When you wrek your enemy laner you should type "é de plasma ou soled?"