Using it right after a Windfall where you force every player to discard and draw 20 cards is a surefire way to get ahead, but even if you only get three mana back, you'll get all the cast triggers from your permanents for free
Like most Magic: The Gathering cards, the value of Wrenn and Seven depends on a few consistent factors: its rarity, the printing and finish (regular or foil), its physical condition, and the set it was printed in (Magic Online Promos)
If you control more than one creature named Contortionist as the last ability resolves, perhaps because you created a copy of the token or created more than one to begin with, choose one of them and use its number of folds to determine how many cards to draw
One of these cards is the Volcanic Island
After sacrificing the Bag, you get to retrieve those cards
Can include showcase magnified commons