The Dawning Archaic {10}
Legendary Creature — Avatar
ColorlessCommander: legal
Identity
Colorless
EDHREC rank
#8,060
Cheapest printing
US$0.99
TCGplayer
Printings
3
This spell costs {1} less to cast for each instant and sorcery card in your graveyard.
Reach
Whenever The Dawning Archaic attacks, you may cast target instant or sorcery card from your graveyard without paying its mana cost. If that spell would be put into your graveyard, exile it instead.
Keywords: reach
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.