There are 40 champions in free champion rotation this week : r/leagueoflegends
LoL Free Champion Rotation Time (6th-13th July)
Lol League of Legends Free Champion Rotation This Week March 10 - DigiStatement
League of Legends: Free champion rotation finally at 14 per week
League of Legends on Twitter: "New free champion rotation: Jinx, Kindred, Malzahar and more! https://t.co/Opp7oMQTR7 https://t.co/jQvWmvF6L9" / Twitter
League of Legends Weekly Free Champion Rotation
League of Legends: New Free Champion Rotation (Season Three: Week 17)