Arrow Volley Trap — ruling 1

You may ignore a Trap’s alternative cost condition and simply cast it for its normal mana cost. This is true even if its alternative cost condition has been met.

Arrow Volley Trap — ruling 2

Casting a Trap by paying its alternative cost doesn’t change its mana cost or mana value. The only difference is the cost you actually pay.

Arrow Volley Trap — ruling 3

Effects that increase or reduce the cost to cast a Trap will apply to whichever cost you chose to pay.

Arrow Volley Trap — ruling 4

You divide the damage as you cast Arrow Volley Trap, not as it resolves. Each target must be assigned at least 1 damage.

Arrow Volley Trap : règles, fonctionnement et interactions (MTG)

Arrow Volley Trap is one of those cards players keep asking about. Here is, in plain words, what its official text says, the rulings published by Wizards of the Coast, and the combos players actually run.

Official card text

If four or more creatures are attacking, you may pay rather than pay this spell's mana cost. Arrow Volley Trap deals 5 damage divided as you choose among any number of target attacking creatures.

How it works : Arrow Volley Trap

Original English text — Wizards of the Coast / Scryfall

#1October 1, 2009· Wizards of the Coast
You may ignore a Trap’s alternative cost condition and simply cast it for its normal mana cost. This is true even if its alternative cost condition has been met.
No other card is named in this ruling.
#2October 1, 2009· Wizards of the Coast
Casting a Trap by paying its alternative cost doesn’t change its mana cost or mana value. The only difference is the cost you actually pay.
No other card is named in this ruling.
#3October 1, 2009· Wizards of the Coast
Effects that increase or reduce the cost to cast a Trap will apply to whichever cost you chose to pay.
No other card is named in this ruling.
#4October 1, 2009· Wizards of the Coast
You divide the damage as you cast Arrow Volley Trap, not as it resolves. Each target must be assigned at least 1 damage.
No other card is named in this ruling.