Complex sentence: The top six lottery prizes ever (the amount won by a single ticket regardless of how many total winners there were) are all Powerball tickets, four of which were won after the Powerball became a $2 per ticket game.
Split into simpler sentences: The top six lottery prizes ever (the amount won by a single ticket regardless of how many total winners there were) are all Powerball tickets. Four of which were won after the Powerball became a $2 per ticket game.