Bastion Inventor is a common Creature — Vedalken Artificer card from The List (PLST), collector number AER-30. Current market price: $0.23, TCGplayer market prices via Scryfall.
Improvise (Your artifacts can help cast this spell. Each artifact you tap after you're done activating mana abilities pays for {1}.) Hexproof (This creature can't be the target of spells or abilities your opponents control.)