How did I get Corki for free?

I played LoL months ago and began saving IP. I intended (and still do) to buy runes upon hitting level 20, using just free heroes until that point. Recently I started playing again with a friend who was surprised to see that I have Corki "purchased" on my account, who is in the most expensive tier- actually costing more than I've earned total to this point. He's also quite easy to dominate games with, though he seems to have been nerfed substantially from when I used to play.

Was there once a way to unlock him, or was he just at one point substantially cheaper and I splurged without remembering so?

Solution 1:

It seems from the NA forums that everyone who had an account created on january 2010 received Corki with its U.F.O. skin for free.

Those who already had it received an IP boost.

And here is the official quote :

As we promised, because you won the Gamer's Choice awards for Multiplayer, Strategy, and PC Game of the Year, we are giving away the UFO Corki skin as well as the Corki Champion to everyone who registered by January 14, 2010. We listened to your opinions: We are giving away Corki for free to anyone who doesn't yet own him, and for those of you who already do: We're giving you 3 free days of IP boost! These prizes will be awarded by the end of February; our agents are still trying to track him down after his most recent sighting. An updated artist’s rendition is enclosed below.

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