Halsin, Emerald Archdruid {3}{G}
Legendary Creature — Elf Druid
GreenCommander: legal
Identity
Green
EDHREC rank
#13,428
Cheapest printing
US$0.16
TCGplayer
Printings
3
{1}: Until end of turn, target token you control becomes a green Bear creature with base power and toughness 4/4 in addition to its other colors and types.
Choose a Background (You can have a Background as a second commander.)
Keywords: choose a background
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.