Madame Web, Clairvoyant {4}{U}{U}
Legendary Creature — Mutant Advisor
BlueCommander: legal
Identity
Blue
EDHREC rank
#12,179
Cheapest printing
US$0.22
TCGplayer
Printings
1
You may look at the top card of your library any time.
You may cast Spider spells and noncreature spells from the top of your library.
Whenever you attack, you may mill a card. (You may put the top card of your library into your graveyard.)
Keywords: mill
Every printing
highest TCGplayer market first; a card with only a thin single listing shows its low
In short
A Commander deck is a commander and 99 other cards, one copy of each (except basic lands), all inside the commander's colour identity. Paste a full list into the deck price calculator to price it and check it against the format.