Aether Vial is a uncommon Artifact card from Mystery Booster 2 (MB2), collector number 216. Current market price: $1.72 (foil $17.33), TCGplayer market prices via Scryfall.
At the beginning of your upkeep, you may put a charge counter on this artifact. {T}: You may put a creature card with mana value equal to the number of charge counters on this artifact from your hand onto the battlefield.