PokerStars Tournament League
Unfortunately, only the Initiation Level tournaments are free, and you can only play those for the first 3 months after joining PokerStarsSchool. Initiation Level tournaments have a prize pool of just $5, making them essentially worthless on their own, so there are definitely better freeroll poker tournaments to consider. However, if you plan to play lots of freerolls each month, the Initiation League has a $300 monthly Leaderboard (with a $100 first prize). Only your top 6 results will count towards your Leaderboard score.
The Master Level monthly Leaderboard has prizes totalling $1,500, with $500 for first place. However, Master Level tournaments cost 25¢ to enter (including a 3¢ fee). For the Master Level Leaderboard, your top 12 results each month are counted. There are 16 Master Level tournaments each month, so if you are serious about grinding this Leaderboard each month, you will want to participate in each of them to maximize your chances. Make sure you join the PokerStarsSchool if you want to compete on the Leaderboard! You can also compete in the Master League and Initiation League at the same time.
Compete in The League for a portion of the $1,500 prize leaderboard in the Masters League with @PokerStars Click to Tweet
The League used to be MUCH more profitable, offering 4 levels. All tournaments were free and the Master Level Leaderboard offered prizes of $15,300! Even the lowest level's leaderboard offered $1,218 in prizes.
Honestly, if you're good enough to be able to regularly compete for the Leaderboard prizes, you would no doubt be better off just playing regular MTTs with higher buy-ins. However, if your bankroll can only handle 25¢ tournaments, then you might as well play tournaments that also have a leaderboard - it's essentially a chance at bonus money!