As Six-y Beast enters the battlefield, you secretly put six or fewer +1/+1 counters on it, then an opponent guesses the number of counters. If that player guesses right, sacrifice Six-y Beast after it enters the battlefield.
Near Mint - $0.50
Near Mint Non-English - $0.50
Lightly Played - $0.47
Lightly Played Non-English - $0.47
Moderately Played - $0.40
Moderately Played Non-English - $0.40
Heavily Played - $0.30
Heavily Played Non-English - $0.30
Damaged - $0.25
Damaged Non-English - $0.25