Like most Magic: The Gathering cards, the value of Duress 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 (Secret Lair Drop)
Its cleave cost lets it scale into a full counterspell, letting you keep pace with big haymakers while still dominating commander-centric play
If it's a rarer card, you will need to spend a certain amount of Trade Tokens, depending on its rarity
To sum it up, if your local gaming store is full of Aggro, the deck is sure thing
Chatterfang, Squirrel General Chatterfang, Squirrel General adds a very interesting token twist
It's a bit clunky, and it would be nice if there were a better, cheaper option that you could do at true flash speed without breaking the bank, but it is workable if you're willing to not have any mana rocks in your deck