Riot Games is bringing Chroma Packs back to League of Legends. For those of you unfamiliar with them, you'll be able to basically recolor your Champions' skins with them. You can buy them for your champs (Zac, Morgana, Darius, Caitlyn, Master Yi, and Tristana are featured) for 590 RP (Riot Points) each -- some require the purchase of (or for you to already own) a premium skin!
Point blank, these should be free upgrades given out to players who master or otherwise play a ton of games with specific Champions. Heroes of the Storm does just that, offering up three different color schemes per character per skin, and sports the same type of free-to-play model