League of Legends is the first free-to-play game done right, no time blockers, no power ups you buy, nothing that gives you an extra edge. It's fully free and only thing you can essentially buy is new champions and/or their skins, which give you no extra power. It's created by Riot Games a company that has strong values that always put the player first.
Careful though, it's highly addicting!
"League of Legends is a fast-paced, competitive online game that blends the speed and intensity of an RTS with RPG elements. Two teams of powerful champions, each with a unique design and playstyle, battle head-to-head across multiple battlefields and game modes. With an ever-expanding roster of champions, frequent updates and a thriving tournament scene, League of Legends offers endless replayability for players of every skill level."